Any law is ultimately enforced by the government. There isn’t a different type of law to which the constitution doesn’t apply (I mean it doesn’t say a ton about limiting various types of laws—laws around contracts, state law, etc etc—but it still applies, it just doesn’t say much).

However, this seems more like an issue of corporate policy than law.

Github needs to have some policy that ends up with them taking down repos that actually host illegal content, they don’t have any legal obligation to host files, so they can respond to takedown notices by just taking down the files. This wouldn’t be the government forcing them to take down files, it would be them deciding not to try and parse the law very closely. But this is different from having an area of law where the constitution doesn’t apply, and it bears repeating, because the constitution is really important and the idea that there should be some sort of cutout where it doesn’t apply is bad for society.

Something we should grapple with as a society is whether poorly written, ambiguous laws should be interpreted as the government taking action by essentially forcing companies into be over zealous in their corporate policy.