Gamer is a signifier for multiple concepts, one of which is simply "anyone who enjoys gaming as a hobby" but a more specific one is roughly "a demographic in the Western anglosphere, ages 14-35, largely male, being marketed to by gaming corporations and the military, who see themselves as a 'class' associated with their gaming identity, and participate in that culture". The usage of the term in reference to the latter, or something like it, has been common for over a decade now, which we can see with early gatekeeping of the term (supposedly fake gamers, a judgement especially targeted at women), as well as both ironic and unironic identification as a "gaming" class (they targeted gamers and gamers rise up and gamers are the most oppressed demographic etc).

So the essence we're trying to invoke with this signifier is the people who strongly identify as gamers, who were caught up in gamergate with all the vitriol and misogyny that came out of it. Gamer an adopted consumer identity rather than an inherent or socially-enforced identity, so if it doesn't describe you then you don't have to identify with it.

Most people play games, but only a subsection of those are obsessed with wokeness and rage at the thought of non-white or cishet representation in video games. But that subsection is the most active in consuming games, or at least particularly vocally represented in secondary media.