In fact, it is this "discrimination" that defines them as religious organizations.
If you have any doubts about this, just go to your local Catholic priest and ask him to officiate over a bar mitzvah for your son.
*chuckle*
But how many Jewish people will ask for a priest?
How many gay people will demand to be married in the church of THEIR choice? An will be willing to go to court to force it? I think the recent kerfluffle with the bakeries will be a memory. The SC will be flooded with cases. And we have seen how fair they are.