the interesting thing is when a country actually banned bitcoin (example Bangladesh) nobody even talked about it and there were no drop whatsoever!
these things will surely slow down the progress of bitcoin (and possibly any other decentralized cryptocurrency like bitcoin, but has no effect on centralized altcoins) because it will make the adoption harder. for example merchants won't accept bitcoin as payments anymore in those countries. but it can never stop the adoption. bitcoin is still a decentralized currency and will be adopted by people and grow bigger.
additionally it is only rare cases when a country actually bans bitcoin. the rest of the world (80% of them) have adopted bitcoin one way or another. like Japan with open arms and easy regulations and no taxation on bitcoin payments or like US with a bit more strict laws regarding taxes,...