First, I agree with the sentiment that "I don't like" and "I am not a fan of..." in a trade response often has nothing to do with personal feelings and is just a way of saying the owner isn't interested in that player.
Second, I couldn't care less about how I feel about a player personally. FF is a game - I play to win.
As an example, I couldn't stand Chris Carter when he played for the Vikings. I thought he was an absolute tool. Now, if I had been playing fantasy football then, and I could get him, you better beleive I'd be emailing his owner every offer I could think of.
My reasoning is simple (part of which I have already stated) - but also, I don't actually pay the guy. Being on my FF team doesn't help pay his salary or "reward" him - I am not "supporting" him in anyway shape or form. Now, that doesn't mean I am going to watch a game he plays - I'll just check the box score and hope he puts up yardage and gets in endzone.
Now, this is different than if a guy has "character" issues that could affect playing time (waves to Big Ben, and his former teammate Santonio Holmes). That I definately take into account and try to shy away from as they tend to just become bigger issues over time (points at TO) - not smaller.