Police have all these weapons, and they want to use them, instead of first trying more constructive, peaceful methods.
The theory is that tasers are a (edit: partial) replacement for firearms for cops. The reality is that approximately 0% of cops are willing to draw a taser if they suspect that someone else has a firearm; they go for their firearm too.
Instead tasers have replaced other methods of de-escalation and containment, which is very bad if you're not a cop. Combine this with cops being called out for people experiencing mental health crises, and this is a recipe for disaster.
Tear gas is not benign, it is nasty stuff that has already killed people. Some preliminary research points to it potentially damaging the lungs of people who are exposed to it for a long time, possibly permanently.
On tear gas, CDC has https://emergency.cdc.gov/agent/riotcontrol/factsheet.asp :
People exposed to riot control agents may experience some or all of the following symptoms
immediately after exposure:
* Eyes: excessive tearing, burning, blurred vision, redness
* Nose: runny nose, burning, swelling
* Mouth: burning, irritation, difficulty swallowing, drooling
* Lungs: chest tightness, coughing, choking sensation, noisy breathing (wheezing),
shortness of breath
* Skin: burns, rash
* Other: nausea and vomiting
Long-lasting exposure or exposure to a large dose of riot control agent, especially
in a closed setting, may cause severe effects such as the following:
* Blindness
* Glaucoma (a serious eye condition that can lead to blindness)
* Immediate death due to severe chemical burns to the throat and lungs
* Respiratory failure possibly resulting in death
Coughing and shortness of breath are especially nasty during the COVID pandemic.
And none of blindness, glaucoma, immediate death, or respiratory failure sound especially fun.