Duolingo is not for people that wants to learn a language, it is for people that wants to want to learn a language.

I disagree. I would rather say that Duolingo is not a silver bullet for lazy people who want to easily learn a language. However, it's a great tool. Like any tool, you may or may not like it, but that doesn't make it useless for everybody else.

Learning a language is just hard. The more you practice, the better. Find tools that you like, and put effort into it.