The problem is the disproportionate force. The police should not be using those weapons. If an officer panicking goes this badly, we shouldn’t be blaming that officer or the protest. The problem is that police were firing bullets into a protest, at all. That this was a plan they had on the table for this situation, and they’re clearly happy with this plan.
You’re right, I didn’t mean to say they’re not at fault for shooting people. What I meant to say was that we shouldn’t get tunnel-vision either and assume that officers just need better training or vetting to make sure they don’t miss or don’t shoot as early.