A Taser device is perfectly safe, right until it destabilizies your cardiac conduction system and kills you. When your family objects, you get litigated into homelessness. Welcome to US justice.
You'd rather they used the traditional lead bullet approach to law enforcement? I wouldn't.
I'd accept that tasers are merely "less lethal" rather than "non-lethal", but if being taken down by a cop I'd choose to be tasered rather than pumped full of lead. I can't quickly find a good reference for the lethality of tasers, but subjectively it looks to be in the order of 1 per 1,000 uses. I'll wager that is a whole lot better than firearms, and probably not much worse than pepper spray's unintended lethality.
If anyone can come up with a truly non-lethal device that can incapacitate, I think you'll find the cops would happily use it - if only to avoid the bad publicity and paperwork of killing suspects.