All businesses and services should have an absolute right to refuse service to anyone for any reason or with no reason at all. When anyone objects to such a decision, all individuals should have an absolute right to refuse to do business with that particular business or person for any reason or with no reason at all. There should be no government involvement in such choices/squabbles.
Exactly correct. That is freedom of association.
I cannot be legally forced to associate with anyone I choose not to associate with.
Therefore all anti-discrimination laws are unconstitutional.
Discrimination may be stupid (it greatly decreases your customer base for one thing) but it is a constitutional right.