Tactful ways to inform people that they're playing badly?

[RoyalBeef]

If that’s the full extent of it I’m fine with it, it’s when people start posting about other people’s numbers esp in casual content where it becomes an issue.

Hows that an issue? As you say yourself it doesn't matter in casual content, so why would you care about someone posting about those? Also I still highly doubt it happens half as often as people claim. I tried plying DRG. I sucked. My numbers sucked. If someone would hve called me out saying my numbers sucked, I would have agreed with them because I was alread shaking my head at myself. How many people commented on my numbers? None. Zero.

You feel entitled to sh*it all over endgame players, calling them toxic, cheaters, potential dangerous criminals irl (lol), and then act outraged when you get bombared with smug and cynical responses.