>We had fun in online games without kernel level nonsense.

You might of. But there was a percentage of players turned away by cheaters or even just had a bad experience one day because of one. At scale this can cause a bad experience for a ton of players so trying to stop as many cheaters as possible does matter.

>Why do I need to compromise my hardware

You don't have to compromise anything. In fact it is optimal to have the system be as secure as possible that way cheats can't mess with the game.

>How do old boomershooter communities tackle cheaters?

By limiting the rate of new players. This goes against the wishes of games who want to achieve massive growth.

>When and why do methods that work on a social graph fail or necessitate anticheat?

If people provided IDs that could work too instead of anticheat, but usually people do not want to do that just to play a game. It adds friction to the onboarding process.