I figure it's kind of always been that way, no? Online games inheritted it from local games. I've never tried to win a game of poker, and every game I have won if from tilting "pros" off their game because "I don't bet right".

You can even see it in tabletop roleplaying. Where you're "not supposed to meta-game" or "you can't have a lawful good lich (who's ultimate goal is to live long enough to save the town from evil collegues)" or "someone's got to play healer" or whatever. I always like subverting norms to see what happens. A group of clerics on a quest for an ancient tomb might need to convince/coerce some local muscle. The lawful good lich lets everyone play with themes of racism and prejudices. A group without a healer is kind of just playing on hard mode because there's no safety net.

But lots of groups won't go for those kinds of things, or will only allow them occasionally.

I just play for fun. I win by having fun. The score is somewhat irrelevant.