A lot of self-identified gamers are really just guys who subsist off a boom/bust hype cycle, culminating in games that are, for the most part, relatively easy to play, complete and move on from.
And, as you can see on GAF quite often, they openly resent the games that exist outside of this bubble. Both because of the lack of the hype cycle part, and because the gameplay in many indie games is often intentionally unlike the biggest releases.
The narrow view of the hobby by this type of gamer even extends to other massively popular games that don't operate on the hype/release cycle. Look at takes by the average GAF user on games like CS:GO, Dota 2, PUBG, Civ, etc. They're often deeply disconnected from the reality of what those games are, and almost always written from a condescending perspective.
Fan communities will always be susceptible to hype in a way that leans negative, but I think it's particularly egregious in video games. To the point that the history of the medium is largely a subject of complete disinterest, games that released six months ago essentially irrelevant. Always on to the next thing. Perhaps it's because video games established themselves at a time when marketing evolved into a particularly potent beast, cutting off many from the roots of the more intimate communities that sprouted up around music, literature, comics, etc. early on. There are smaller communities that work more like those other fanbases -- some on this forum, even -- but the ur-text of video games is Nintendo Power.
People who are openly aggressive about their gamer "identity," and protecting it from outsiders, often demonstrate a dim knowledge of the medium as a whole that would mark you as a neophyte or dilettante in any other fan community. The mark of a member of the gamer "ingroup" is not really about interest in the hobby or the medium, but the ability to fiercely engage in the buildup for whatever comes next. Don't spoil announcements bro!