Without having any sort of insight into police behavior, I'm assuming two likely options:
1. They are given rubber bullets and mace without any form of de-escalation training, so they just use the tools they have at their disposal.
2. Just like any kind of organism, the police force needs to preserve itself and make sure it is necessary. The military doesn't like peace, and the police cannot thrive with peaceful protests. They do what they see fit to make themselves irreplaceable.
I can't speak to your experience, but I've been in multiple riots, and you are right, teargas make some peaceful protestors violent and angry.
From what I've seen, teargas and mace are used after a small minority of protesters become violent and the crowd is lawfully ordered to disperse.
I can't say if these are the right tactics, but I have not seen police use these things for no obvious reason.
The one situation where this wasn't the case is when peaceful protesters were blocking one of the two roads that was going to be used to transport multiple heads of state off of a peninsula after high level discussions. I assume this was due to some security consideration, but I don't know. The crowd was passive.
Police do use teargas and mace for no reason. There are dozens (hundreds?) of videos of exactly that from the last week, including an aerial shot of Seattle PD instigating with mace at point blank range on protesters who were behind a barricade.
* https://www.facebook.com/omarisal/videos/10220021035848747/ - Livestream of 30+ minutes leading up to the incident. The interesting stuff starts at 26' in, but he gives a lot of good context on the protest leading up to then. The livestreamer was at the front line when they started pepper spraying, and in fact you can even see him in the aerial footage as he's next to a pink umbrella that makes a good landmark. It's very clear from ground eye view the violence was deliberately premeditated and coordinated by SPD and not in response to any immediate threat. No orders to disperse, or do anything else for that matter, are given prior to pepper spray, teargas, and flashbangs.
* https://mobile.twitter.com/izaacmellow/status/12676798206006... - Official SPD story claiming incident is a "riot" and was forced on them: " Crowd has thrown rocks, bottles and fireworks at officers and is attempting to breach barricades one block from the East Precinct."
I don't think you can watch these videos and come to the conclusion that at least in this instance, it's not the protesters rioting but rather the police. Then they're officially lying about it.
Normally, in healthy police forces, the police is in contact with protest organisers to cooperate on weeding out the violent troublemakers to ensure the protest remains peaceful. This has always been very effective in many countries, including the US, before US police abandoned this approach and started training for escalation instead.
> 1. They are given rubber bullets and mace without any form of de-escalation training, so they just use the tools they have at their disposal.
From what I've heard , they aren't even using the rubber bullets they way they are designed, but instead in a more dangerous way. Incompetence or maliciousness, take your pick. I wager its a bit of both.
1. They are given rubber bullets and mace without any form of de-escalation training, so they just use the tools they have at their disposal.
2. Just like any kind of organism, the police force needs to preserve itself and make sure it is necessary. The military doesn't like peace, and the police cannot thrive with peaceful protests. They do what they see fit to make themselves irreplaceable.