Github already provides a proxy of actual legal identity, at least in the EU. For a business owned org, the VAT id is provided along with validation and billing information must match.

I don't think your OS intends to imply or guarantee a legal entity relationship with every CA certificate in your trust store. It's not even clear what that guarantee, as an end user, would get you: the presence of a legal entity doesn't somehow make that entity accountable to you or your locality.

> I don't think your OS intends to imply or guarantee a legal entity relationship with every CA certificate in your trust store.

I get the feeling that it's exactly what Windows "intends to imply or guarantee", it's just taking a long time to get there. The whole code signing part is trying to create a reality where to be able to create software for Windows, you need to be a business entity, and need to have business relationships with Microsoft - directly, or transitively. Basically, a corporate web of trust.