Nowhere. It always puzzles me why this response always crops up, even when I never even remotely try to claim that platforms have any legal obligation to host content.
I did claim that making their site have a partisan recommendation algorithm is not a good idea and may be bad for society. I have zero doubt that this is their right, but people and companies have the right to do plenty of things that aren't good for society. Saying that it's bad for society to implement a partisan recommendation algorithm is not at all the same thing as saying it is or should be illegal.