Or lets say you have a religion where intravenous injections of heroin are part of the religion. Can the feds still make possession /use of heroin illegal? Of course! Same with sex with minors, or any other behavior associated with a religious belief that is part of a facially-neutral policy that has a reasonable, legitimate purpose.
Here another example of where the bar would be correct.
Many Sikhs carry a ceremonial knife with them at all times. It’s part of their religion.
Now let’s say a bar has a “no weapons allowed” policy. That bar would have every right to have that policy!
And so the bar denies a Sikh with a knife admittance. Has the bar discriminated against that Sikh? No. Their problem is with the knife, not with the Sikh.