It does not happen that way, at least in most states. I post a lot of articles about self defense shootings on freerepublic. You can find them all under the banglist keyword. It is very seldom that a person in a self defense shooting is prosecuted, and even rarer that they are convicted.
Of course, this does vary by locality. You are much less likely to be prosecuted in Texas than you are in New Jersey.
You are right, for the most part. I think it has gotten SOOOOOO much better in recent years. It’s just that some of the cases you hear about are so mind-numbingly horrible, they stick with you for years. I was just venting a bit.