Think honestly about what this means for your view on this.
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.
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.
You are asking a binary question for which there isn't a binary answer. Better to ask are those sex workers doing something they will get a pat on their backs for from other members of society? In a way a builder, chef, firefighter, and even a prison guard would.
Consider the sex workers who deal with mentally or physically disabled adults. Most people have sexual urges, and those who are unable to participate in society in the usual way of addressing their urges with a romantic partner or a one-night stand still have them. There are a good number of very professional sex workers out there who can provide these people with sex (often with specific expertise for the relevant handicaps) and generally significantly improve the wellbeing.
Are those sex workers doing something they shouldn't be doing?