Here's why there's an issue, and why there's a dude in critical condition, and why this is now an anti-war protest (it kinda is/always way, regardless), and is a protest for animals rights, women's rights, minority rights, workers rights, every person's rights...
1) Because it's the Bay Area, which is obvious, and you're like 5 miles from Berkeley and San Francisco.
2) The cops are idiots. They decided to clear people out of the square at 4:30 AM on Tuesday. I mean, who likes being woken up at 4:30 AM, and told to go somewhere else? No one does. They seemingly did this to avoid having to deal with the removal of people during the rush hour (which, btw, is limited anyway). They wanted this cleaned up before 8:30 AM.
This was a bad call.
They then told the protestors they could assemble there at 9 AM, during park hours (or whenever the park opened). So, at 9 AM they all came back. BUT...the city had decided they were going to clean up the park first, etc. etc., so when the protestors came back the park wasn't yet opened up. This created the beginning of the conflict. People were aware they were breaking the law, and couldn't be in the park. They all could be arrested if the city wanted to divert it's manpower from the other crime centers in the area, known by most as "most of Oakland."
Had the police come at 9AM on Tuesday morning, the mayor specifically, and spoke to them all, explaining the situation, things may be different. They would have to leave when the park closed, and they could return the next day.
This didn't happen.
Now people are getting shot at.
Don't get me wrong for I am not anti-police in any way. I just think they handled this situation as poorly as possible. If you want proof of this just take a look at every other OW sit-in nationwide.
This isn't happening anywhere else. But when you have a police for that is used to responding with force in most situations, this is what you get.