Guild Wars 2

It is a PvP community and many types exist: the toxic, the encouraging, and the apathetic. All types have existed since the beginning of the game, so it may be a new experience for you but it is not a new experience for the community. Your experience will differ depending who you happen to encounter and how (or even if) you communicate with them.

How you end up dealing with the salt is a personal journey because it isn’t going to stop and it isn’t going to be punished. Some like it, finding humor or encouragement in it, others take it harshly and struggle to let it go. It used to bother me, but then I realized that being bothered by it only hurts me. I look to see if there is any useful info within the vitriol that is actually worth consideration, like getting called out for making a stupid rotation, but otherwise ignore it.

Responding or trying to reason with them gets you only additional frustration, so I would not recommend it. If you made a legit mistake and you feel like owning up to it, go for it, that has usually been received well or ignored.

Thief? I feel you. Same here.
I was never really bothered by it, actually had lots of fun just reading it, but for some reason it bothers me a lot more when team mates insult other team mates than when they insult me, especialy in Unrank.
In many cases it is a good call to write to the guy who is being insulted and tell him something normal or rather encouraging to go on, because ragers like the guy who is insulting him/ her are partly the reason why some people discontinue PvP.