Sex work is what used to be called weasel words and are part of the same queer politics that took over universities in the 80s and changed women's studies to gender studies.
So by substituting words with real meaning for ambiguous ones you can then make any arguement to further your agenda.
Any one on FWR will be aware of the slippery slope that was caused by more and more people saying gender when you are actually talking about sex. Now there are whole generations of school children who have grown up thinking they are the same.
And when the students educated in the 80s and 90s moved into journalism they change the style bible of newspapers so that this manipulation of deliberately misleading words became not just the norm but the absolute.
And in the same way as those who argue that sex should be a choice they also want the prostitution of women to be a choice, hence sex work.
Whereas, as with gender reinforcing sex stereotypes, sex work reinforces the notion that women with few employment opportunities "choose" prostitution. (Funny how unemployed men aren't expected to make this "choice".) So not only does this mean women become available to be exploited by men, it re-inforces the notion that women aren't worth training or being given education to get better paid and more valued work, but characterises women's "assets" as being her body.
(And I suspect those in social work and elsewhere were also part of the education system that was part of the back lash against women's liberation politics, which was about demanding women's autonomy, at home and in society. But instead reinforces the notion that women or a certain class - and race - will only ever have the "choice" of being prostituted so lets patronise them by pretending it is work of the same status and most jobs.)