In this case, disagreement isn't the problem, it's being snarky that is.

Complaining about downvotes isn't cool either.

Not if what a downvote means changed that drastically recently. I never complained about downvotes, because I believed in the community collective wisdom. However, in the past few weeks, I've seen many cases of downvotes being used to basically communicate that "I disagree with you and your six-paragraphs, coherent, civil post, which is even on-topic, but I'm too lazy to write my own comment explaining why, so have a downvote."

I'm seriously thinking on putting some effort into collecting some examples and starting a discussion on the topic, because it's IMHO very bad tendency.

EDIT: Although in the case of your parent post downvotes are understandable.

pg has said many times in the past that it's OK to downvote for disagreement -- even if a comment is civil, coherent, on-topic, etc. (I usually prefer to voice disagreement in such a case, but don't always have the time/energy.)

It's usually self-correcting. A lot more people can upvote than downvote, and most people don't like seeing good comments in the gray.

Fuck you.