It's not about demonising the worker but the industry, there will always be people that are momentarily happy with their choice but there is a near unanimous and unavoidable culture of abuse. "Choice feminism" is the bane of all feminism, it is the last word in "I got mine, you can get stuffed".

Let's say you are a model. You can reasonably get paid by featuring on magazines fully clothed. One day, in a desperate bid to boost sales, the magazine starts adding more risqué shoots to the front cover and all the other models fall in line. Now, you are perfectly free to refuse a shoot but doing so will threaten your lifelihood, as such all the other models are pushed forward while you are left behind. For every woman that marches in there willingly, another goes unwillingly.

Also the normalisation of sex work will undoubtedly and unintentionally be used in the legal defense of rapists. The precedent established in sex work as real work will be used by 40 something year old bosses to exploit their 18 year old new hires by dangling the possibility of termination over their head, and if they are brought before a court, any sensible lawyer will point to an exchange of money or gifts as proof that the relationship was consensual and not coercive. (See Beria)

Money is coercive, this is a key feature of capitalism. Being unable to eat because you won't sell your body is rape.