You're absolutely right! You then interpreted a response which agreed with you as a problem though, and everything that followed made you look a right tool.

Someone was literally just pointing out that the stigmatisation is ironic given the same logic used in the idiom could be applied to many industries. They acknowledged that it wasn't, and that the stigma was associated specifically to sex workers, but basically were just having a chuckle that the logic used to denigrate a whole industry could be just as easily applied to lots of "respected" career paths too.