"Because that's what I want" is a perfectly good reason - your children should absolutely be learning you are a person like them, and they should aim to help an

"Because that's what I want" is a perfectly good reason - your children should absolutely be learning you are a person like them, and they should aim to help any person achieve what they want if it is reasonable for them to do so. It's not at all the same as "because I said so", which is a claim of authority. Of course, you also shouldn't just frame everything that way, otherwise they won't understand the reasons they should want to do things, and because if it is a "want", that should be weighed up against what other people want and how important it is to them, fairness, etc... which is probably a more complex problem than most.