The problem is that people with government jobs are more likely to support initiatives and policies that promote government jobs-- eg, "mission creep".
Yes, just like every other organization in human society, government is an organization and behaves like an organization. Like most tautologies this is fairly tautilogical.
Comparing organizations like Aetna or Blue Cross Blue Shield to their counterparts in Medicare and Medicaid I would say that for comparable sectors government has a far, far smaller tendency to bloat itself. Government just fights against human nature while private industry fights against economic law when both try to avoid bloat and economic law crushes human nature like a bug.
Whoosh goes the point, apparently--
Pointing out the obvious ("everyone does this, since forever"), does not make the problem suddenly "OK to ignore".
Logically, there is very little difference between the mega-banker creating legislation that makes mega-bankers richer, (corruption and graft, et al) -- and the former govt employee creating legislation that increases benefits and protections for government workers (even when there is no real need or benefit to the society for said increases/entitlements/protections) Both are special interests.
The idea is to eliminate special interest opportunities. Pointing out that "Hey, we have lots of those people, and you want to shut them out!" is like saying "Hey, we have all these lobbyists-- you want to keep them out of politics? Don't they have just as much right to be politicians as any other guy?"
As I pointed out, you can't have the cake and eat it too. There's nothing stopping the mailman from working part time at Micky D's on weekends, JUST to further his goals of one day becoming a politician. The prohibition was not against those people being allowed to enter politics, it was against the enabling of political careers--- For every year in office, so many years doing qualified private sector work needs to be done. The prohibition was against what kinds of jobs were eligable for that requirement-- It's to stop quid pro quo from the revolving door. "Yeah, I used to be a senator, and now have a cooshy gig for the MPAA!", a la Mr Dodd. Government employment is a ready reservior for such quid pro quo, in the form of a garanteed income after doing your "service." That's another reason for its prohibition from candidacy.
If you are a government worker who has no plans to ever run for political office (pretty much all government workers in the rank and file), then such a prohibition will have precisely zero impact on you.
If you are a government worker who has plans to run for political office, then it WOULD impact you.