At least this is the experience in my circle of friends. Got a couple friends who have pretty much only played Dota (or CS) for the last 15+ years and have 0 interest in even trying any other game. There is also the crowd (including me) who play video games in general but these are very clearly different groups.

So this is like saying "football fans are insular to football". I mean yeah they are football fans not "sports fans".