Shy didn't say tanks were effective squishy killers, and they're not. It's a team game. Tanks and the like use CC in order to help their team, not just in order to 1v1 kill someone. You can use Elastic Slingshot to knock Jhin out of his ultimate. You can use Impale to drag that fed Riven away from your carries. You can use Bandage Toss into Curse of the Sad Mummy to lock down the entire enemy team while your own divers go and murder their squishies.
I mean... would you say building AD isn't unfair because it leaves you so squishy you can get bursted? It's a separate issue. (Not that I think building AD is unfair. I have no comment there. Just saying that I don't think your argument was very clear.)