There is no such consensus. Downvoting for disagreement has not only been common for years but even explicitly condoned by pg 8 years ago. It isn't in the guidelines because it isn't a guideline.

So you and Paul Graham both condone downvoting any opinion that you find disagreeable on HN. I respectfully disagree with that policy, and I hope we never cross paths again.

Ahh, the purity of seeing everything in black and white terms.

The topic was "is there a consensus that disagreement is not a sufficient reason to downvote a comment?" I pointed out that there is no evidence for a meaningful consensus even in this thread, with several people arguing in favor of downvote-for-disagreement. I pointed out that historically people have downvoted for disagreement, with links to examples, and I pointed to pg's early statement to that effect.

The evidence is that there is no consensus in HN readers, and that downvoting for disagreement, within limits, is allowed by the powers-that-be.

"Allowed" or "condoned" is different that your unjustified interpretation as "downvoting any opinion that you find disagreeable".

Just because we can send a man to the moon doesn't mean we should send all men to the moon.