Yes, the argument is if you split them up their core value proposition is put into question. Apparently a very large group of users are on board with the core value proposition, and you are imposing on that group a ton of assumptions that the regulatory breakup and oversight will end up "working out better for everyone".

These companies are also vulnerable to competition in a fickle market. Tik Tok has gained massive ground and is on a similar trajectory that instagram was on some years ago. For everyone's claiming that FB stifles innovation, we have an obvious counterexample happening literally before our eyes.