Discrimination is based on sex, race, religion. This is probably legal, but it does paint a big target on her establishment as a gun free zone.
The left hasn’t figured out yet that the bad guys are targeting gun free zones.
Legal question is can a person or entity that maintains a public accommodation legally infringe on the constitutional rights of any individual inclined to engage that accommodation?
They probably secretly know but are not talking about it. It interferes with liberal paradise.