Try not to let it get to you. I've seen people throw out insults to the entire team before the match is even over and the numbers are posted. It's true that some people are new, but it's unlikely that the ENTIRE team is at fault (and you are blameless for the loss). I can't tell you how many times I've heard people say, "You guys are awful," and then I look at the after action report and realize that the person throwing out the insults isn't exactly that impressive. I also love when my DPS partner (I play SMN) isn't very good at doing damage or following marks, yet somehow I get looped into the insults because we lost, EVEN IF I am doing more damage than anyone on any team. Haha. I'll never understand the keyboard rage. It's RNG. Yeah, it's frustrating when you get paired up with people who clearly aren't as good as you, but that's how this matchmaking system works.
If you are a NEW player: DO NOT LET THE INSULTS GET TO YOU. Try to learn from your mistakes, take advice from nice people, but don't let the rude people get to you. If you ever aren't sure of something, feel free to ask on the forums. People tend to be very helpful here.
Now for a fun memory that I think you all might appreciate: Back when Seal Rock first came out, I was running it pretty often. One time, I was in a match with a dude who was literally spamming commands for where to go, what to do, etc. Despite how annoying it was, it had us doing waaaaay better than any other team, and I didn't particularly mind it. But, people on our team decided to start arguing with him. After a lot of back and forth insults, people vote kicked the guy who was spamming commands... but after booting him out, no one took charge or gave commands. Our team fell behind and ended up losing because someone decided to start an argument and boot the leader out. It was really counter-intuitive.