To return to the original argument, I think that it is being forgotten that tribalism (or at least the specific political tribalism of the us) is very much a two way street, and that the act in question (allegations of sexual predatory from the "other side" causing those 35% of people to just be more likely to vote for him) is the very example of tribalist action/reaction.
I've complained a lot about American liberal/democrat tribalism here in the past, but trust me, that is definitely because it is the kind most expressed here on these particular forums by people whose thoughts I care about. I don't think democrat tribalism could be said to be to blame for republican tribalism. While it's true that while you shut yourself away from others you also shut others away from you, I've only really seen the liberal tribalism bloom out in the last two or three years. Meanwhile, the conservative side has been tribalising itself for pretty much as long as I've been aware politics exist. And I think that the example of people reinforcing their support of this Alabama guy makes a very clear, very extreme example of that.
Because I mean holy shit, even Sean Hannity and his production team after their first reaction had been to support the guy, apparently went "wait a sec we can't actually be actively supportive of that" and changed their narrative of it a bit.
To sum up, I don't really think "these 35% is possible to be blamed on democrat/liberal tribalism and their condescending thoughts of and actions against republicans/conservatives" is an argument that holds water. It is roughly how tribalist thinking works and reinforces itself, that's true. But I think that seems like only looking at half the picture and forgetting that those people are people too and people do have control over and responsibility for their own reactions and behaviour and aren't just drones mindlessly responding to external stimuli. And I feel like even if because of your own tribalism your gut reaction is to defend a possible sexual offender against 14-year-olds that should also be an immediate shock signal for yourself to go "hey wait how did I just react" about yourself.