1. All sex workers are women.
This is a good myth to begin with, because the conservative view of sex work as something exploitative is predicated on the idea that all of its victims are women. In fact, there are many men who also choose to participate in the broad spectrum of work that makes up the sex industry. But because men are generally assumed to be less vulnerable to sexual exploitation than women, we tend to view their participation as something different and more autonomous. (What man wouldn't want to get paid to have sex, amirite?! etc.)
The collective cultural view of the sex industry is still one in which women are thought to make up the subjugated parties and men the johns who benefit from them. But what happens when men are the ones pulling a pay check from providing sexual services? And what does it mean if women are the ones paying for it? Would a woman buying the services of a female sex worker be less likely, in our view, to exploit her? Would a man purchasing time with a male sex worker be able to treat him the way we imagine female sex workers are treated? Undermined, degraded, exploited? Or would all of these transactions occur in much the same way as each other – occasionally enjoyable, often as expected and sometimes requiring action unfavourable to those workers involved.
In short, kind of like a normal work day.
2. There's no such thing as real choice in sex work, because no one would ever choose to sell their body for money.
It can be tricky to understand what constitutes the notion of inviolable choice. To some people, sex workers are women to be pitied, either pawns of the patriarchy with no agency of their own or poor women who've had to resort to "degrading" themselves to make a living.
The reality is a little more nuanced than that. A sex worker (and let's assume in this instance that it's a woman) may indeed be poor and untrained enough for socially sanctioned careers to ensure that her available options keep her hovering around the poverty line. On the other hand, she might have a middle-class background, a tertiary education and no apparent "need" to choose an option that so many sanctimoniously assume to be the last resort. While sex work for both these women may just be a way to earn a more than decent income, improving the stability of both their finances and her family (if they have one), it might also be something they enjoy as much as any other kind of job if not more. Validating (and shaming) sex workers based on your interpretation of their circumstances undermines the very same autonomy and choice the sex industry is often accused of denying women.
Much like any career field, the sex industry is staffed by women (and men) of all different backgrounds. Some come from privilege, and have had all the benefits of education that are supposed to "keep" women out of a career path seen as both shabby and tawdry. Do we need to "save" them as well? Or are they entitled to their choice because we assume their privilege allows them to make it more freely than the women we speak for, but not to?