If the liquor license really limits who can be denied service, then I don't consider this to be retaliation. By analogy, if a lawyer is denied entry because th

If the liquor license really limits who can be denied service, then I don't consider this to be retaliation. By analogy, if a lawyer is denied entry because they are black and they sue, that isn't retaliation it is just requiring the business to follow the law. If a lawyer is denied entry for some legitimate reason (say drunk and belligerent), and they dig up some other unrelated offense to sue about (while ignoring the hundreds of other establishments with the same minor offense), then that is retaliation.