Back in the day when I still played FFXI we'd occasionally get people logging into the game who also played WoW who would crap on XI in shout chat. They would also do so on the XI forums. You'd also get WoW players who would actually be those players that complain about everything while in XI and not understand some things the XI community did as in player etiquette ect. A lot of people moved from XI to XIV and some still play both. Even back in 2.0 on some servers you'd get WoW players in dungeons and take offense at people giving advice on how to play certain rolls like tank mostly due to how they work differently here than in WoW. There was for a time a part of the WoW community who would go down the whole oh well FFXI is just trying to copy WoW line of thought even though XI was out two years before WoW started.
Obviously some things are different between XIV and WoW and not everyone who plays XIV played or plays XI. But just like loldrg and calling Lalafells potatoes are persistent in XIV the "ugh WoW players are the worst" mentality comes from years of it being a thing from XI. So, it could be seen as an old feud between two families where it's been going on for so long the newer people brought in don't understand it.
