Person A is friends with person B. Person B likes to abduct, rape, torture, and kill women. Person A knows this, though has no part in it, yet remains friends with B. Is it acceptable to question A's character and distance yourself from him based on his friendship?
The problem here is that A does in fact have a part in it. His/her knowledge makes them take a part in it, because they can and should intervene. Once A becomes aware by default he/she acquires a responsibility. They may or may not live up to it, and depending on whether or not they do, with very, very little possible exceptions, the almost certain outcome is that failure to meet this responsibility reflects terribly on that person. For clarity, the responsibility can be met
while maintaining the friendship, for many possible reasons. Person A might have reasons to want to remain close and be helpful to person B, but they have no excuse to not
try and do something about the horrific harm which is being carried out.
So, questioning is not only acceptable, it's a necessity. If one doesn't question the friendship and fails to attempt to look beyond the surface (to find out what person A has or is doing about it), they would be extremely irresponsible towards themselves and towards society. In short, it'd be crazy
not to question them.
As for distancing one's self from them, generally, of course it's acceptable. Both for the mere maintenance of friendship with B and for the more specific reason i explained above. And it would not necessarily be guilt by association. Simply put, if the person concludes that A is a rapist, kidnapper, murderer and so forth too, then yes, it would be unfair. But distancing one's self from person A is not by necessity based on such conclusion.
Generally, we have many reasons and inclinations in regards to who we decide to be close with, who to associate with, and who to not. Depending on our goals, preferences and position in life. A simple example, if i have kids, i might be much more careful about what
possibilities i allow in my circle, unlike now. By highlighting possibilities, i'm specifically indicating that it would not necessarily be based on absolute judgments on certain people. Rather, just what may simply come from allowing them in, and i wouldn't be wrong in doing so.
More down to earth, if you know people who simply aren't "good" people (selfish, racist, what you find to be good traits is relative) and others, who know of these same traits are friends with them, is it fair to judge their character and distance oneself simply from the association?
The logic goes similarly to the above, with a few more things to put in mind. The first example is drastic; it's clear cut. This is more difficult. By my standards, i'm not necessarily a good person in the first place. But, to avoid over complication, i'll get to the gist. I have one friend who i think is clearly a 'bad' person. As in, more bad than good. He has done things i find intolerable, and his thinking generally is extremely disturbing to me. I find a lot of what he might do and have done to be very unethical.
I've considered cutting my relationship with him many times, and have attempted to do so more than once but changed my mind when he tried to fix things using promises, because i wanted to give him a chance. To be clear, those things are mostly unrelated to me personally, but they are things i find unacceptable. I'm trying to be what i perceive as a positive influence on him. And throughout, my feelings remain a bit uncomfortable. Sometimes i decide it's a hopeless case, sometimes i think there's hope and see a minor change, and sometimes i want to beat him up. Similarly to the above, i also have a responsibility here, because some of his views and actions can and do result in harm to others. I try to live up to it.
If someone was to realize some of this person's negative aspects, and
questioned me because of that, i wouldn't consider them to have done anything wrong. They must question me. If they decide to distance themselves from me, again, i wouldn't necessarily think they've did anything unfair to me.
It would depend on why. Have they concluded that by necessity, since i'm friends with him, i'm just like him? If so, then yes, they've misjudged, thought about the matter in an incorrect manner and have made an unfair judgement as a result.
However, if they decide to distance themselves from me simply as a way of distancing themselves from him, for example, then i see no problem with that. Allowing him to be close to me is my choice, and others are free to make their own, depending on their goals, preferences and position in life.