How many parents force their children into a mold of what they would have wanted for themselves? Note that I say what they would have wanted, not what they see to be what would be best. Consider those children who start doing something (like getting lessons on an instrument or in dancing) at age 3 - there are very few who truly enjoy it enough to justify the hours and hours they spend learning it - I mean, who knows what they may or may not want to do at age 3? All that you can be sure of is whether a child enjoys it in the moment that they are doing the thing, but so many parents control their children to such a degree that there is no free choice in the matter.
Would Mozart have chosen his vocation had he been given the option to choose? There is no way to know, but that same question could be applied to any child who went through rigorous training programs from early ages.
In some circumstances the parents force their children to do these things because it may be the only way out for the child - the only way out of a life of poverty - so the parent pushes their child to excel in the hopes that the child will be good enough to elevate themselves to a position of greater wealth and stability. China would be a well known source for examples in this context, but it is definitely not the only one.
Then you have other circumstances where the parent(s) deeply desired something for themselves and then project and impose that desire on their child(ren). Some parents failed at achieving their desires for themselves and so try to live through their children, while other parents did realise their dreams and still impose those dreams on their child(ren) for a number of possible reasons. It may be that they want their child to have the life they had, but are not willing to accept that that is not what is best for the child. It may be that they believe that their child must want it because they themselves wanted it. It may be that they have created a value and belief system around this desire which they have now tied in with the way they value their child. It may be that they regard the child as an extension of themselves and so believe that the child will naturally follow in their footsteps. Whatever the reasons, some parents push their kids hard from a young age to master some skill.
It is rare that a child is given any choice in the direction of their life. It is rarer still that a parent will do what is best for the child, as opposed to what they want for the child or what they think is best (without really thinking it through). Apparently children are not allowed to make their own choices a lot of the time. Apparently they don't have the capacity to decide for themselves - but how does this belief give a parent the right to impose something on a child like training for hours every day? A child should have the opportunity to explore and investigate and experience as much as possible so that they can find out what it is they do like - in this way the child has the best opportunity to make an informed decision for themselves, obviously within the understanding that some things change and that they may not be making this same choice a few years down the line.
Too many parents want to be gods to their children - "obey me or face my wrath!". Too many parents want to rule over their children's lives and try to shape them into whatever mold they have in mind. Even worse, most parents are not aware of how much they influence their children, even when they are not doing it deliberately. Which crime is greater, shaping your child into whatever shape you want deliberately or in ignorance?