That doesn’t follow. In an illiberal country they’ll just ban any large platform that allows anything. How would free speech absolutism on a platform or in some other country have any impact on a state like that?

Banning a platform outright isn't as easy. Some countries like Russia are absolutely willing to do that, but a lot of smaller illiberal countries still need to curry favours with their own population and banning a popular platform will cause some unrest.

For example, Turkey banned and unbanned Facebook several times.