And people who use water intentionally to cause death or serious harm should face harsh legal consequences.

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.

So if you throw water at me I can throw a lit firework back at you? Same thing?

That's why drowning somebody or attempting to drown somebody is a crime. Just like using fireworks as a weapon against somebody.