Everyone bitches about supports having damage and AP, but trust me, when it's gone, you'll beg for it back.
Nobody likes to support. This is because all of your power is invisible. It doesn't feel good to spot out plays with wards (especially when your team is behind and you can't actually contest it). It doesn't feel good to randomly get jumped on by a mid laner and destroyed with no ability to defend yourself or even try to fight back. It doesn't feel good to sit in a fight and have no visible effect on the fight (from your team's perspective) -- or even worse, initiate the fight and die in the process. It doesn't feel good to run in circles for fifteen minutes in laning phase watching another player play PvE tower defense. It doesn't feel good to hit the mid game and have nothing but a gold generation item and a sightstone while the other members of the team are finishing two items. Yes, your CC chain or initiation or healing and shields may have won the fight for your team, but the person you're shielding or peeling for gets all the glory. And when anything goes bad, the support is the first person blamed (along with the jungler). It's a thankless job full of flame and toxicity, and nobody wants to do it.
Then AP supports happened. Now, instead of the standard initiating "tank" supports that aren't actually tanky because they have no items or the full utility supports that can't defend themselves in a fight, champions that feel good to play well have started filling the role. More people started playing supports because it felt good to support. Queue times shortened, less people were autofilled, and League of Legends became a more enjoyable experience with less toxicity.

How many times have you had a game where you load into champ select and your support says "autofilled support feelsbadman" or "can I have top?" (/mid/whatever) Or maybe you're the autofilled support, and you have to play a champion you have no idea how to play. You have a thousand games apiece on Ashe, Caitlyn and Varus, but they don't mean anything because you're now playing Nautilus or Soraka, who have entirely different skillsets and nothing you know from your marksmen translates over. When you're trying to remove AP supports, you're saying "I want to be autofilled and have no idea what I'm doing more often". AP supports are the solution to autofilled supports.