However, rights not exercised are lost.
Do we want to live in a country where “sacred” books are not allowed to be burned, if we own them?
I do not.
You could say the exact same thing about the Klan, could you not? After all, if you stop parading around in white sheets with pointy white hats through the middle of black neighborhoods, we might just lose the right to parade, right? Or, maybe not.
Just because someone exercises a constitutional right that they have - like burning a book, or a flag or submerging a cross in a jar of cow urine - doesn't mean it's a smart or insightful thing to do, nor does it guarantee other people's right to do it later. Some times doing a douche-baggy thing is just being a douchebag. This just might be one of those times.