There have been bad apples in this game all along.
In Heavensward I got the pet from the Vault and the other dps said "Of course the [censored] Black Mage got it..."
And in Alexander I once had someone call me bad, rail on me for being bad, called in a guildie into the raid (a randomized group) to also call me bad...
"Hey, Gale, I hear you are really bad at this game!"
I died.
"Confirmed!"
This moment is sort of burned into the back of my skull because I took it pretty hard. I'd already been having a bad day for real life reasons.
Which brings me to my point: They've been here all along, maybe you're just noticing them more. Also, in regards to thin skin... I mean, yeah, you shouldn't take things personally but also people need to remember that those other characters on the screen in raids are being controlled by actual human beings somewhere. Being polite is always best.
As a WoW refugee myself I can say that WoW is not as over the top toxic as people make it out to be. In my experience I've run into harsher but less frequent toxicity here (like the above example) while WoW is basically just a stream of trash talking that turns very quickly into white noise.