Feminists point out the social expection of the availability of women's bodies for use. They have been and will continue to be accused of oppressing and marginalizing johns. It's a straightforward situation in which johns are identified as engaging in unnecessarily "taboo" sexual behavior by society, just like lesbians and gay men, and thus you should afford them the same consideration and lack of criticism if you are a Good Liberal.

Feminists who point out objectification and the expectation of sexual access are slapped with the label "SWERFs" (sex-worker exclusionary radical feminists). Meghan Murphy writes quite a lot about it so see her other pieces.