And the counter claim that 4e is the new hot ### and better than anything before it is not?"If you are playing 4e D&D, then you are not playing a real RPG."
"If you are playing 4e D&D, then you are not playing true D&D."
It most definitely gatekeeping what constitutes who is or isn't playing D&D or an RPG.
Is 4e D&D actually D&D? For some edition warriors, the answer was "no." 4e was not regarded as a valid expression or truth about being a genuine form of D&D play.
The traditions and sacred cows where not just done away it, their slaughter was celebrated and anyone not liking it was told at length how bad they were and how great 4e is for finally getting rid of them.
The "Gatekeeping" around 4e really goes both ways.