Was your post only saying that? That you agree with DHH? In that case you got those downvotes for adding a useless comment to the discussion where a simple upvote would cut. Your agreement or disagreement without a story backing you up means nothing to the reader. Don't take it the wrong way.
The temptation to write 'you must be new here' was resisted (for the most part), but it was tough (and mostly because I think I'm 'new here' myself).
As for upvotes being on post quality, that may have been once the intention but it seems that has long gone out the window. Imo that degrades the quality of HN quite a bit but since you can't really check why someone got modded down I guess it does not matter much.
People that mod down because of disagreeing with you would have done so anyway even if that would not have been policy.
And those that mod up/down based on post quality would probably do so too.
Any change you perceive is probably more related to how the numbers of those groups develop.
