The majority of sex workers online are not.

How do you know? Most prostitutes still have to advertise.

Because the umbrella is big enough to cover people selling nudes, I suppose.

That is often illegal. It's not illegal in the US. Even there, it is often a leader service for illegal prostitution. https://twitter.com/KristineParkerH/status/16625082178076426...

It does not appear to be justified to make claims about what's true of "the majority of sex workers online". This is not an area where reliable numbers exist.