It is not legal I guess

People think that the word keylogger sounds dramatic but that's not something what only intrepid people can use. I used it a couple of time this keylogger https://www.refog.com/keylogger.html seems to me the best one . I needed it to control my kid's actions on the net. You know I try to be clear of his things but .. sometimes a little bit of control is a must !

It's okay to use them to spy on your kids and stuff.
Some people think that it's unethical to do that.

I know a lot about keylogger and I just can't assume why people think that it's something extraordinary ?
It's just a common sense and not only hackers use it but also some people who want to learn some information.
Do you use it and how often?