It's not OK. We edit it out of posts when it's small and inconsequetial to the rest of it. When it's woven deeply into a post, we downvote it for being "not useful" — or even actively harmful — to the health of our hobby. Particularly bad examples that count as any or all of "offensive, abusive, or hate speech" can also be flagged as such in addition to or instead of downvoting.
Gamers get unfairly stereotyped all the time. We don't need to put up with that here. Subsets of gamers get unfairly stereotyped all the time too, and we don't have to put up with that either.
Especially for subsets of gamers, stereotyping often happens in daily life, and yet another poke in the eye from a thoughtless or intentional stereotype during what is supposed to be fun leisure hobby time is the last thing we want to experience or inflict on another.
As curators of this site, it's our job to make it not a needlessly hurtful experience to our readers, especially those who get it regularly in their daily life. As a site that I hope represents the very best of the gaming community, we should be a safe, welcoming place for all gamers.
To be not just tolerant, but actually welcoming, to all gamers, we have to be intolerant of some attitudes that are thoughtlessly or deliberately hurtful. I think it goes without saying that if it comes to a choice between a person and an attitude, it's the attitude that will be made unwelcome here.
Our regular curation tools are effective for this: downvotes, editing, comments requesting alterations, and flagging are all excellent ways to show what is and isn't a good post.