It amuses me how the very first response to this thread is someone blaming WoW and 124+ people agreeing with them. So far in my experience, the bulk of the people I have met are old XI players who switched over at some point, a scattered few that are burned out on the Pandaria expansion or from other games, and many, MANY more brand new to mmo players than I would have expected. I think this is mostly the console crowd coming in that are brand new to mmos. They never picked up XI because of the bad press and by the time this game was on Playstation it was mostly fixed.
So the idea that somehow a toxic WoW community came over here and is shitting all over "your" game is absurd. Toxic people are toxic no matter WHERE they came from, and blizzard has done a lot over there to help curb some of the more obvious trolling that happens here. Over there you don't just get a blacklist option, you can report someone at the same time without filling out a long form. You can replace people in your dungeon with friend if someone loses connection - you don't have to ask someone to fish for an in progress and hope its yours. There is a lot more to foster a community feeling across servers, so no, WoW doesn't "breed" toxic players. If anything, the environment here and the focus on playing with strangers rather than friends is what breeds the toxicity.
A lot of things are broken here. The market economy is a joke. Systems that should be intuitive and automatic are for some reason convoluted and manual. Content that is being added is only half-finished (if that) and frustrations are mounting at not being able to just... play the freaking game.
I blame SE more than I would blame any one group of people that has come to play the game. We all have the same goal: to be entertained and enjoy a world apart from our own with our friends. The systems should facilitate that, not rail against it like the ONLY way to properly play is by pairing 4 complete strangers together.