The same type of people that exist in FF XIV exist everywhere else on the internet, including WoW, and mentor status has little to do with it. I've seen way more salt thrown at mentors trying to help than mentors throwing their own. There are good and bad mentors, but some people like to lump them all together which isn't quite fair. It is THAT mentality which caused me to remove my crown, though I still try to help if and when I can. But...this thread isn't about mentors, it is about something else entirely.
If there are a lot of people coming over from WoW, it is as I said earlier in this thread, no one would be able to tell. People are going to be people no matter where they are or what they're doing. That said, a bigger population also increases the chances of running into jerks. There isn't any denying that. They just stand out more from the rest of the crowd while the rest quietly takes their place among the rest of the population.
That also said, I have noticed that some people in this game seem to have a superiority complex when it comes to FF XIV and WoW, in that they believe their game is superior in each and every way and they can't come up with any reasons other than "FF XIV looks pretty, WoW looks like crap. That's why!" Meanwhile, WoW players are currently like "this game sucks right now, go play FF XIV. It's actually fun." A game can be pretty, or it can be ugly, but the game play is what matters at the end of the day imo.