One of those is not like the other. Prostitution is illegal in most places, so I don't have any beef with them avoiding it.

Porn is legal, and should not be discriminated against, but that's beside the point. The business in question was providing 100% legal services for adults, but nothing to do with either porn or prostitution.

Are you saying it is ok to discriminate against a business just because their services are oriented towards adults and not children? If that is the case, then Stripe should also discriminate against "straight" bars and pubs, which is not the case.