Think honestly about it. Do you think I have anything against sanitation employees?
Public sanitation workers keep our society functioning, they're a cornerstone of civilization.
Online prostitution, on the other hand, ranges from providing 0 value, to extreme negative consequences, such as the current porn addiction epidemic, or the loneliness epidemic.
The fact that you think profession B > A only reinforces my point and shows, precisely, that GP's argument does not work.
In all of those cases I would council her to the best of my abilities on safety and long-term planning, if she'd let me. And of course, as any parent, I would worry about her safety. But hey, I'd worry if she went paragliding or mountain climbing too.
Honestly, I would be more disappointed if she became a lawyer in the pocket of, say, Amazon or AirBnB. Or a politician for some extreme right political party.
Would I be happy if she was a sex worker in some seedy part of town with a pimp hovering over her? Of course not. But that is not dismissive of sex work as such, rather of exploitation and coercion. All of the examples above avoid that.