Actually, seems that’s more the rule than the exception in US national politics. People routinely support liars, sexual predators, con artists, war criminals … provided they’re from “the right” party.
To them, it’s not “misplaced”, but more of a “lesser of evils - and the other side is so much worse” tradeoff.
So it depends on specifics of the case at hand. For example, not to pick on him, but Guido is Dutch. As such, for cultural reasons he’s prone to a certain directness and honesty that often strikes (among others) Americans as brusque, rude, and/or insensitive. “Meh” to me - so it goes.
And I lost count of how many times an executive at a startup I’ve worked for was charged with sexual harassment. The outcome was always the same: nothing actually happened to them, but the entire company was sentenced to days of “sexual harassment prevention” training, as part of the deal the bigwig cut to get off easy. By now I must be one of the most highly trained people on Earth in that specialty 
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That’s how the world works. In your case, vote out the supporters standing in the way of the outcome you want. But be forewarned that you’ll probably find that relatively few others will join you. Most people, most of the time, don’t want to rock the boat. Not even if it’s sinking.
Overall, yes, I favor making it harder to terminate membership. You favor making it as easy as legally possible (I think - would it actually be legal to say rejecting a motion to kick someone out would require unanimous “nay” from the Board? if so, you should push for that).
I don’t believe there’s an “objectively right” (or “wrong”) choice to be made there. De gustibus non est disputandum. Either way, there will be winners and losers.