I guess most people here have never been in public safety or law enforcement.
The number of drug-addled, violent, danger-to-themselves-and-others people encountered in the US is unusually high and increasing.
This is compounded by the inability (right now) of the justice system to either put them into either suitable treatment programs (with mandatory detention, essentially) or incarcerate them (a gradual but steady decline in prison space and willingness to hold and prosecute them - this is a real problem).
When you have someone crazed out of their mind, hitting/punching, shouting obscenities, spitting and biting at you and others on the street, being polite isn't going to cut it.
Of course it's worthy of debate whether administration of drugs like this are appropriate and desired by the public at large. But defined as a law enforcement tool just like non-lethal weapons, they are (currently) totally legitimate to use to subdue someone who's being violent and a harm to self and others.
The mistake here was the wrong dose, not the principle. Mistakes happen, it's our job to make sure they don't happen normally.
Please don't join the knee-jerk protest against some symbolism that police are using this to "torture" people or commit some atrocity. Especially if you've never even been near someone exhibiting psychotic rage (and who likely just committed property damage or violence against another person). You act based on a symbol - depriving public safety and law enforcement of tool after tool because you see one or two bad examples - but then don't ever have to deal with the consequences of your choices for the rest of the law abiding forces acting to protect you every day.