I hate the argument of shoot the leg. Police are trained to shoot center of mass. Shooting a leg is a very bad idea. First off, the leg is a smaller target. Second, the leg can move more readily than center of mass(barring shooting at Neo
). Third, there are major arteries that run through the leg. Fourth, a leg injury does not ensure the person will comply. Fifth, an injured person can sue for the hardship of crippling them(it's happened).
If you need more reasons, I can give them to you. But the biggest, and most common argument is the same reason they do not normally aim for the head. It's a harder target to hit.
It is the police officer's job to protect the citizens. They, for the most part, try to do so as safely as possible. However, If it comes down to a police officer dieing or a perpetrator dieing, I'll go for the perp. The dead offender cannot kill a person, and the officer can protect another life. I've had my share of run-ins with the police.
Sadly police are people too. Meaning some are good and others are bad. Just be glad you aren't judged by what actions the worst in your field do. I mean recently we had security guards robbing convienience stores. Should you be judged by their actions? Should you be treated like a potential robber just because of your job. These stories are a gross exaggeration of the real situation. I'm sure we can find a few stories of security guards that killed people.
As to the suit against the Tazer. It was because the Tazer was marketed as "Non-lethal" which implies that it cannot kill. They have since revised it to "Less lethal" to more accurately express what it is.