Cum facials have been popular not just in gay porn though, like any "factory" job, safety glasses required on the shop floor. Usually, because someone messes up, injures their eye, its gets reported to OSHA, then becomes a "bad mark" against the company or worse, the person can than sue the company for "safety violations", then the company can enforce safety glass OSHA rule to all its employees.
All it would take, one of these porn performers, gay or straight, to get an eye injury while on the job. But it does not sound like "the company's" (studios) care much as long as its performers act in a responsible manner. If anything, instead of mandatory safety goggles, maybe all facial's will no longer be allowed, as a viewer, I would be ok with that. It would not account for the occasional shooter