For those discussing the analogy of wearing a uniform while doing something (like buying a drink) sounds like it is laid out in the company bylaws as a no-no.
I think the argument is really that there is no rule against kneeling - thus him getting not hired - when there is little to no other work options, for breaking a rule that doesn't exist falls pseudo 1st amendment rights issues. So, Seattle stating they are cancelling his interview for potentially not violating a rule that doesn't exist is somewhat troubling.
Do other individuals need to sign paperwork? If so, how are we determining who signs what?
Things get murky fast.