I'm still missing the context for the nautilus nerfs.

I don't get why he's getting these nerfs, especially why it's both together. He is the only tank I've seen been picked in lcs consistently, the rest have all been fighters. Poppy isn't played much anymore, Maokai isn't played much anymore, pretty much no other tank is played at all except Shen. And all the other tanks have low win rates, especially as of the spring playoffs. So why is it that the only tank that is picked consistently, that isn't Shen, is getting nerfed? And why so hard?