Why is porn and casual sex normalized, but prostitution stigmatized?

Hookup culture is so normalized that people who don't engage in it feel ashamed, but I don't see anybody shaming people for casual sex. However, it seems prostitution is still heavily stigmatized, people will shame those visiting escorts for objectifying women, using them as sex objects, etc. but somehow don't apply that analysis to hookups, or have concerns about trafficking (which is valid) but don't apply the same analysis to the porn industry (which has the same issues). Also casual sex also has problems with roofies, alcohol, date rape, sexual assault etc.

Even back in grade school, it never really made sense why loveless casual sex between two strangers is okay, but it's not okay if one pays money (okay if it was indirect like drinks or dinner though), and it's okay again if you film the encounter.

In traditional cultures, all 3 are seen as bad, sex is seen as something special to be shared between married couples who have devoted themselves to each other. In a sex-positive culture, you would expect all 3 to be seen as good, with proper guardrails like legalizing and regulating the sex industry to prevent exploitation and trafficking.

Why is seeing an escort seen as a red flag for a relationship, but having many hookups is seen as valid?