Silencer is a situational pick if anything and I agree with him being bad as a pure support, but he will absolutely destroy certain heroes. His aura is a pain in teamfights too, even if he doesn't have items and the opposing team is competent.
I played a CM game last night where we ended with a Bane and a Tiny on our team. I told our Captain to ban Silencer because he literally shits all over Bane and Tiny, but nope, "Why would they pick Silencer?".
They picked Silencer and we got trashed in 70% of the teamfights. I'd start channeling my Fiend's Grasp (I was the Bane Elemental) and then suddenly "SILENCE" and then I was just standing there, while our Chen got stunlocked and focused by the enemy team. I think we had two helpful Hand of God casts that entire game due to chainstuns, aura silences and global silence.
We did get outplayed, but holy moley can Silencer screw with you in a teamfight if he is positioned right.
He was their solomid too.