A police officer does not have to be endanger to use a taser. He or she can use a taser to keep from being put in a dangerous situation. That means if you are ordered by a police officer to comply and refuse he has the choice between fighting you and tasing you. Fighting you can be dangerous so you get tased. Your choice. He doesn't have to just stand there and keep telling you over and over.

Now there are a few cases we it looks like someone was tased when they shouldn't have been but it isn't different then when they would use a nightstick when they didn't need to. Most of the case I see people getting upset over the person who got tasered was at fault.