Any technology is crackdownonable, since it is in the end used by people. If the government says "if you are caught/seen using X, you will go to jail for life," it is a major crackdown.

I am not saying this will stop Bitcoin, but it might severely hinder it and cripple it. Bitcoin will not be "turned off", but if there are no exchanges, no apps on the App Store (because Apple wants to be compliant with laws), what will you do?