No, I explained that already in my comment. It was in an edit, maybe you drafted your reply before that. I said:

> The point is not that every explanation will be understood, but to at least demonstrate that there is a reason for preventing fun things, even if it's complex and confusing.

If I tell my 3 year old that watching too much TV will affect her concentration, I absolutely don't expect her to make a complex long-term value judgement, or even to know what the word "concentration" means. I also don't expect her to just say "oh fair enough then". As I said, it's just to demonstrate that there is a reason (even if she doesn't understand it) beyond my own satisfaction.

Can you really not see that there are three possibilities here:

1. "I don't care if you're upset, so that's what we're doing".

2. "I don't want you to be upset, and although there's a good reason, if I can't persuade you logically then you can have it your way"

3. "I don't want you to be upset, but there's a good reason, so that's what we're doing"

(Edit: Having written that, the last one is still not quite right. The point is to acknowledge why that have that feeling - not just assert that they're upset. Usually it's pretty simple e.g. they want to carry on playing. But it does take more effort than either of the other approaches.)

> I sometimes see parents ...

In my experience (from casual observation), the very worst behaved children have uncaring parents that shout and scream at them.