Solution: don't let your kids use internet-connected devices until they are of the age where they are capable of independent thought. Making App Store stricter won't fix anything.
Technology is a tool. It is dangerous precisely because it is powerful. Don't give technology to people who are not responsible enough to understand this, instead of trying to restrict its power for those people who can actually deal with it. I hate how the big tech companies continue to infantilise their users.
Incidentally, is it just me, or does it seem that Americans are obsessed with trying to protect their children from all possible harm?
Disclaimer: these are all just my honest observations, not assertions.