2 things.
Child labour laws came AFTER child labour dropped to almost zero, only leaving children working on family farms...and the labour laws kept that as an exemption
Also ironically there's more labour now than in the past due to the number of family run businesses where childrens work is kept off the books
2. If the age of consent is to protect children then I guess we shouldn't be letting children make life altering decisions...like changing their gender?