I don't see this as debatable. There is no Escort Board of Ethics. Escorts don't take an oath upon receipt of their certification. They aren't employed by a government agency, airline, hospital, or even spa that requires equitable treatment and legal nondiscriminatory practices.
An escort has the right to employ whatever rules, terms, preferences, quirks, or biases for who they choose to meet. You have the right to have nothing to do with that escort.