5. The Education System Is Terrible
The wizarding world may have mastered transfiguration, potion making, and how to make a sport unfathomably dangerous (you just add broomsticks and cast iron balls bewitched to hit everyone) but an effective education system is just beyond their grasp. Official wizarding education doesn't begin until wizards and witches are eleven years old and capable of controlling their magical abilities, which means that wizards and witches spend most of their formative years where they are most receptive to knowledge just hanging around their family homes doing nothing rather than learning basic life skills like literacy and maths from a qualified teacher. And when official education finally begins, Hogwarts is the only school of wizardry in the country. So if you get expelled or are just having a bit of a crap time there and decide to leave, your only options are to go abroad, have your parents home-school you, or abandon your education altogether. It also seems that Hogwarts has no entry requirements for students apart from being able to perform magic and doesn't make an attempt to screen out the ones who are potentially dangerous before giving them a huge amount of magical knowledge including jinxes, hexes, and how to set things on fire. All the stuff Voldemort did in the orphanage when he was a child like making a rabbit hang itself should have been a big alarm bell to keep that child as far away from a wand as possible.