I am currently a freshman in university, and so far I have gotten along well with a select group of friends, which I will refer to as friends A, B, C, D, and E.  I live in the same dormitory as A, B, and C.  At the beginning of the school year, A and B got into a really heated conflict/argument, and it ended up becoming pretty personal, with A getting so mad as to yell at B that she was a "disgusting person," and the 2 have been avoiding each other ever since.  I personally did not see what the conflict was about, and although the 2 kept avoiding each other, I would still regularly hang out with both of them individually and try to avoid talking about it with either group.  Ultimately, C, D, and E all took to the side of B (some of them had witnessed the conflict and some of them had not), and I decided that I could not fairly judge who to take sides with so I decided to remained neutral.

Flash forward to a few days ago, and I have been hanging out with A fairly often, and A really only hangs out with me.  I am still friends with B, C, D, and E, and we still regularly hang out and go out together, but I spend a lot more of my free time with A.  One night, after me and A came back from a party and were both fairly drunk, we ran into B, C, D, and E.  A stayed fairly quiet when we saw them while I started to make conversation with them.  As I was wrapping up the conversation and about to leave, A loudly made several rude remarks to B and walked off.  Later that night I heard B, C, D, and E talking in B's room about how shitty of a person A is.  They kept calling him names and attacking his character, while also mentioning that I have shitty taste in friends and that they don't understand how I keep hanging out with A.  I did feel bad about this, as I know A much better than they do, and although A can come off as a bit arrogant and brash (he was featured on a pretty highly up voted post on r/iamverysmart), A has opened up a lot to me about some shit that he's gone through and I don't think it's fair to just call him a shitty person like they were.

A ends up coming into my room, mad that they are talking shit about him, and proceeds to rant about them to me, attacking the character of not only B, but C, D, and E as well.  A then complains that, in this conflict he has no one on his side, and that I should stand up for him and defend him because we are supposed to be friends.  He acknowledges that I didn't want to take sides in this conflict, as I never join in while they talk shit about him, and as I always try to avoid talking about it- but A argued that I should be more assertive and defensive of his character to my other friends when they start talking about him.  I continued to refuse to take either side, and said that he should respect my wishes to stay out of it, especially since I have to see B and C all the time.  He then accused me of only liking him because he has connections to fraternities around campus and could thus get me into parties.  At this point, I was pretty fed up with him for saying that and I just told him to leave my room if he thinks that little of our friendship.

After some reflection, I feel like I definitely could have handled the situation better, and at least made a promise to A to defend his character if I were ever around while they are talking shit about A.  I have reasoned that doing this isn't necessarily me taking a side, as long as I start to defend B's character whenever A talks shit.  Maybe I should start being a better friend in general.

Am I the Asshole for not defending A?