You're not thinking more than one step ahead. If you let a third party define who "has ID", "is human", etc. you give that third party control over you. You already gave control of your attention away to the sites who host the UGC, now you also give away control of your sense of reality.

At any point they can tell a real human what they can and can't say, and if they go against their masters, their "real human" status is revoked, because you trust the platform and not the person.

If we want to go full conspiritard, we could accuse those of wanting to control speech to be the financial backers of those flooding social media with AI slop: https://www.youtube.com/watch?v=-gGLvg0n-uY -- this fictional video thematically marries Metal Gear Solid 2's plot with current events: "perfect AI speech, audio and video synthesis will drown out reality [...] That is when we will present our solution: mandatory digital identity verification for all humans at all times"

I am though. In the world I live in I already have to give power over myself to corporations and a government, I don’t buy this as an argument for continuing to let internet companies skirt existing laws.