Just because sexual orientation is not a "protected class" on a federal level, employment laws in nearly every state are very clear that in addition to the protected classes, you can not discriminate arbitrarily.
But it doesn't matter, in New York (SONDA) and just about every blue state has very clear anti-discrimination laws when it comes to sexual orientation.
And of course, regardless of the laws, nobody would allow this person to represent them or work for them.
This guy needs to be terminated immediately, his behavior is totally disgusting and reprehensible.