There is a difference between downvoting someone for disagreeing
with you and downvoting someone because they are wrong
. Many of the worst nodes are ones with some fundamentally false assumption. Sometimes the error is explicit, sometimes it's only attitude. Sometimes another monk has pointed out the mistake in a reply and sometimes the original poster has been previously informed.
Downvotes are used to convey disagreement, whether we like it or not. For this reason, noone should take downvotes too seriously. Complaining about downvotes usually attracts more downvotes, just because it indicates you're taking XP too seriously.