First off, note that you are speaking statistically, here. And worse, you're speaking in terms of poorly contextualized statistics. Finally, it's not a question of whether they are as racist as Republican's, merely racist enough. Republican's don't even factor into the equation.
My point is that most places in the midwest do not act anything like you described, and I've lived all over it. In Chicago downtown, in Chicago suburbs, in small town Wisconsin, in medium town Iowa, in small town southern Illinois. Nowhere do any of those communities remotely approach not caring when people die as an entire constituency or applauding death penalties for people who shoplift $10 of cigars or whatever... regardless of race.
Yes, there are small pockets of people who think that way everywhere. They do not significantly affect voting. Yes, the entire community is often a bit racist insofar as not caring if black people get pulled over more often, or segregating neighborhoods on their own. But these minor racist things are
very Very far cry from saying "Good. I want those black thugs dead." as a jerk reaction. or as a voting influence.
So when you casually make claims like that about a nearby county that at face value shouldn't be much different than any of these other ones, I am immediately suspicious. In order for that community to be so dramatically more racist and violence-endorsing than other ones around it, I at first expect there to be significant differences in things like demographics or politics. Somewhere so different should have some very unique, easily detectable differences about it! Things that might explain why it would be so different than regional baseline. I researched these things and found that not only is that not the case, but the opposite is suggested -- it's even more democratic and more black than other midwest communities that I already know don't act like what you described. So from demographics, it should, if anything, be more tolerant than those nearby comparison communities, which I already know are much more tolerant than what you laid out as a description. So by basic arithmetic: more tolerant + green flags of things that should increase tolerance even more = not a super convincing case for a place where people scream for blood for black misdemeanors.
But that's just first blush. Of course, if there are special factors to consider, then it can still be believable anyway that it's different. You didn't mention many or really any of such things until this post, where you suddenly piled on a big paragraph listing them all:
What demographic and voting records indicate they're going to oppose the Prosecutor over this? Do you have a shred of evidence of why a white-flight county, bordering a majority black city, with a long history of police abuse and coverups against black citizens, a place which regularly tops the charts for "most racist place in America", located in the state that regularly tops the charts for the "most racist state in America", the home of the Dredd Scott decision, a county that is 23% black and yet 80+% of those black people live in one neighborhood in the county despite the fact that there is no economic difference between them and the other neighbourhoods - the divisions are solely racial, and the neighborhood went from 70% white to 70% black over a mere 20 years as whites moved out when blacks moved in, a county where the Klu Klux Klan is still active and handed out pamphlets at county high schools as late as 2007, a county where despite being in a largely black district bordering a majority black city, the average white resident does not interact with black people as a regular occurence, where most of the white counties have had larger protests in support of Wilson than they have in support of Brown.
Okay, so that's getting somewhere. (Some of) these are definitely the sorts of things that might be special circumstances that would explain this place being different. Other stuff is pretty irrelevant seeming in my mind. (And none of it has any citations, which still gives me pause.)
White flight/neighborhood mixes -- Almost everywhere I've lived has had white and black neighborhoods and this doesn't really seem to correlate with extreme racism IMO. I can see how it MIGHT, depending on the specific motivations, but other motivations are benign -- people are often more sexually attracted to their own race and more likely to have single race families, and races go hand in hand with culture most of the time, which means greater comfort and friends with similar interests happens to co-align with racial neighborhoods. OR it can be because of hatred. Simple existence of such divisions doesn't tell you which motivations are at play either way. You need more info.
Police abuse history -- So what, this might but doesn't necessarily imply anything about the community's opinions. The primary national problem here in the first place is lack of police accountability to their communities and that they often don't represent the neighborhood.
Most racist place in America -- clearly relevant if true, but I tried looking this up, and 1) I don't see these communities on any lists, and more importantly 2) I couldn't find many lists actually based on data. All of the ones for smaller areas and towns I found were simply people rattling off opinions, which is pretty dumb, because that's just somebody's personal prejudices about where they think personal prejudices are...? Lol? The few research-backed lists were only by state that i could find, and Mississippi and Alabama seem to consistently win, not Missouri.
KKK involvement -- I've seen KKK around a few times in other places. And it has not seemed to matter. The critical question here is whether it's 6 idiots who get together on weekends and walk around? Or is it like, a massive hundreds of people rally? If the latter, then you might have something important there. If the former, notsomuch.
Pro Wilson rallies -- Also clearly relevant, however you stated it in a way that makes its importance ambiguous. What matters is not whether the Wilson rallies were larger than the Brown rallies within the white communities. What matters is whether the SUM TOTAL of Wilson rallies in the entire county is higher than Brown. For example, if 500 people march in Ferguson for Brown, and 25 people march for Wilson in a few white areas, that still would suggest that the county as a whole is more inflamed about Brown. If however, the white area protests for Wilson are almost as large as the Ferguson rallies, then it's an excellent point. Need more info.
In general, though, you're making very stiff allegations about this region being full of pretty horrible people by description, compared to various other communities within a few hundred miles of them.
And extraordinary claims require extraordinary evidence. So far, not feeling very extraordinary, but if you have more refined information on some of those points, then that could certainly change things.
I'm not Ferguson native expert -- But I do think it is only fair to start by assuming they are at regional baseline of decency, and then adjusting opinions based
only on specific, concrete evidence. Otherwise one isn't much better oneself about making snap judgments than the very people one is condemning for doing exactly that...