Legal experts suggest that the restriction violates the Constitution. The basic reason why the martial arts is prevalent in oriental countries is the fact that weapons of any kind are not allowed. People will always be able to come up with a substitute, and sometimes that substitute will be worse than the what's banned. The Chinese government doesn't allow many people to own guns. But that doesn't mean it's safe in China.
Explosives are readily available for mining or construction.
Today, they just steal explosives from construction sites in addition to martial arts. Personally, I'd rather be facing a gun. But the fact is that government itself is the ultimate corrupting force. They hobble business with conflicting regulations and confiscatory taxes, then they expect them to continue to produce new products and new profits for them to tax. Like California's attempt to blame the electrical utilities for the rolling blackouts that are plaguing the state because of their own government policies, they punish business for making a profit while brazenly availing themselves of a large portion of that profit.