Yes definately that is true some country have this rules but the issue is that if you can observe at a very close range you will notice that majority of those teen dont abide to this rules they fake their age and keep working online.
What I think is that if such country really serious with what they are doing all the website suppose to have verification process before they accept any citizen for work.
Making money online is very easy but the ultimate part is that you need to have knowledge and skills on which feild you want to indulge yourself