Why do people hate noobs? Because they suck and make the team fail nine times out of ten. That's why.
I don't like losing because one teammate went 4 - 20
Back when I played PvP Halo, sometimes I was in the situation where teammates performing poorly caused us to lose the match. But as long as my own performance wasn't bad, I didn't care. If my K/D for the match was at all positive, or even 0, I didn't get frustrated. I knew I did my best, so I felt no reason to get upset at my team losing the match.
Conversely, sometimes I would get a little annoyed with myself if I went negative during a match, even if our team won. What I'm trying to say is that my own performance has a far bigger effect on how frustrated I get, than that of my teammates. What mattered to me, more than anybody else's performance, was how much I contributed to the team, whether we won or lost.
Even when I play Warzone Firefight, I've been in situations where I'm the only one calling in reqs to complete the objective, and we end up losing because I can't do everything by myself. This is somewhat frustrating, but I don't let it get to me that much, because I know I did my best and that's what really matters to me.
So why get angry if your team lost the match? Why hate new players when you can still do your personal best? The only reason I can think of is that your W/L ratio matters a lot to you. If that's the case, and you don't play with a full team for whatever reason, then you just have to accept the fact that your W/L, and possibly other tracked stats, are influenced by whatever random people you get matched up with, to some degree. If you can come to terms with that fact, then you'll probably be able to relax a bit and stop hating new people so much.