It may indeed be impossible to ban bitcoin in the long term, but in the short to medium term? It would IMHO be very messy should a major economic player attempt such a thing.
Imagine the US gov. shutting down coinbase/bitstamp/etc, even declaring jail time for those that are caught using bitcoin after the ban. Bitcoin investors would panic and most bitcoin holders would make a mad dash for the exit, cratering the price. It would almost certainly end up recovering eventually (as you said it would require a NWO to ban completely), but who knows how long that might take; in the meantime btc wouldn't look so good as store of value even to those not directly affected. I feel a ban from a major nation such as the US or China would not be a negligible event, and I would imagine Armstrong is thinking along those lines.
It would be a great opportunity to back up the truck and fill it up with BTC at lower prices, because this would be the US government shooting themselves in the foot.
The worst thing a government can do is ban something only to have the population give them the middle finger and it be proven that the government is impotent. From there, Bitcoin would skyrocket in price as it being shown how powerless the government is to ban it.
You are too fearful because you are a short-term speculator. Long-term crypto-currency investors understand that this is a paradigm shift for the world and they understand they are going to be very wealthy over the coming decade.
Weak hands will be thrown off and end up not being wealthy.