Religious liberty is in our First Amendment. Would a church be discriminating against someone by not performing a gay marriage? Would a mosque be discriminating against someone by not allowing a Jewish party at the mosque? SCOTUS already held that Hobby Lobby could not be forced to provide insurance coverage for certain drugs that violated their religious beliefs and therefore discriminate against those employees that want those drugs.
There is frequently tension with Constitutional rights that butt up against each other. The courts have striven to find ways to accommodate both rights using the undue burden rule.
