People keep referencing Bennett's "Character Issues" but my Google-fu is weak and I want to know. What's the deal?

I asked in the comments on the trade thread, but the only answer blamed Fox News. Is it a political thing? He sat for the anthem? I'm not trying to stir shit up, I just want a straight answer. Some comments call him a dirty player, and others say he's locker room cancer.

Edit: I understand (now) that this is mostly a political thing, but I would ask you all to stop downvoting each other. I asked the question, and I appreciate hearing both sides. Links are better, though. Upvote those.

Edit the Second: Seems a lot of people have strong feelings, but little in the way of actual information. It doesn't seem to be simple or straightforward, either. I have to go to work now, but keep at it. I'll try to compile links and summarize what I find tonight, if anyone is interested.