What is the logic of SRD content inclusion & exclusion?

Quote from CunningSmile >>

Quote from MaedraDawnkeeper 

& this isn't just the US market they feel compelled to hog IP in. A lot of others have much harder to maintain IP control in if someone were to challenge such.

Yes, I am an intellectual property abolitionist.

 While I agree that the century plus of copyright protection the US has as a result of Disney political lobbying is far too much if you abolish it all together there’d be no incentive for anyone, from huge corporations to instagram cartoonists, to create new IP if they couldn’t profit from it. So yes, you’re advocating for the abolition of intellectual property as you said and not intellectual property law which is what I think you probably meant  

 That's what I meant.

I want things to go faster into the public domain.

All of Disney's efforts to keep Mickey Mouse and Friends have hurt everyone else.

Not really, no.

Anybody can make cartoon mice and ducks and such, even if Mickey and Donald belong to Disney. Anybody can make a gothic horror TTRPG with a tragic vampire villain, even if Strahd belongs to WotC. Heck, look at the success Paizo has with Pathfinder and the worldbuilding and lore. That's the whole reason the SRD has been such an invaluable tool for third-party publishers. The mechanics are ready to go, all the third parties have to do is create their own lore, which doesn't take no effort, but certainly doesn't take so much effort that it's impossible for fantasy TTRPG companies to make their own stories without access to Drizzt.