Is it like an unspoken hollywood rule?

That teen actors and actresses have to sing as well as act?

Most of them are just better at acting. Most of there voices aren't mature enough for singing just yet.

Yeah, I know what you mean. It is so stupid.

I used to like some of them, oh well. Never trust a celeb huh?

They annoy me to no end.

Are you answering your own question? What?

They usually do it because they are exploring their talents, they don't just wake up one day thinking I'm going to be an actor and never try anything else. Besides, ever considered that maybe they just need the money they earn with those performances?

I think it's ridiculous.
Half of the teen stars act 100x better than they sing.
Honestly..
Most are tone deaf.