I think it's only one religion in the 21st century that kills people for mocking/criticizing it.
en.m.wikipedia.org
en.m.wikipedia.org
en.m.wikipedia.org
Remind me, when were Monty Python killed by Christians? Or the South Park guys by Mormons? Or Woody Allen by Jews?
A good start might be to look into murders and deaths in Pakistan and India of people who mock Hinduism. And you yourself wanted the Mafia to do something about the case this thread is about. So there's 2 examples of different religions already. It might be more commonly Muslims in the west and/or reported in Western media more often recently, but have you considered there may be reasons for that? You seemed to be admiring how Saudi Arabia handles foreigners who disrespect their official religion, but I'd argue that they are a big reason why radical Islam is the way it is, and copying their example is both a bad idea and unchristian. The Sermon on the Mount establishes that I think. But there's also the Samaritan Woman at the Well and the Roman Centurion's Servant to base that on. Frankly, I don't care what impact it has on the price of oil, we should've stopped being their allies and sanctioned them as hard as we are sanctioning Russia long ago.
In any case, you never said how we could define religious speech to ensure we only banned the type of behavior you wanted banned. You said you were using my "narrow definition" but I didn't define anything and clearly it needs to be side I obviously didn't understand correctly what you meant. But this is kind of leading me to my point. It's going to be difficult to define and as a result there will be unintended consequences, it's possible they will cause worse problems. Which takes me back to the other question you didn't answer: should freedom of religion trump freedom of speech or freedom of assembly?
I think it's important to think about these questions, because anyone can criticize and say "We should just ... ", but when you actually have to reason it out, you realize it's not so straightforward. I enjoy playing devil's advocate for that very reason. Often taking the position against what I believe helps me refine my thoughts.