Each time a religious leader (or anyone else) says "don't talk to that person" then the listeners have a choice. If the leaders then say not to listen to the first ones then those people have the same choice and so on.
The only power they have is the power that people give to them. They can ask, but they can't compel (and if they are using force to do so they have broken other laws).
Yes, they use coercive and manipulative techniques ... are we going to ban advertisements next?
if threatening someone will be hated by his God and loose his life everlasting (after being df'd for associating with a df'd)is not intimidation, I don't know what is!
It is only intimidating to someone if they choose to believe it.
That's why it's very different to the kind of discrimination and intolerance shown to groups based on what they are.
It's all about choice and you can't legislate to have people make good ones.