So you admit that fireworks are known to cause death and severe bodily harm. What sort of prison sentence would be appropriate for attacking people with such devices?
In fact, let's use your argument. People drown accidentally in swimming pools regularly. So then if some "protester" decided to set up one of those portable pools and forcibly hold people down under water in one, wouldn't they be guilty of attempted murder?
Using things that are known to cause death and serious harm in a way that is intended to cause death and serious harm is in fact the thing I'm against.