Downvotes are frequently used for disagreement no matter what the intended use is supposed to be. Heck, a lot of the time people assume comments are misinformation when the person voting just disagrees. People often upvote misinformation because they agree with it too.

But feel free to keep telling yourself that everyone is using votes the way they are ‘intended to be used’ instead of how they are actually used which is ‘I agree that this is accurate and/or find this funny’ or ‘I disagree with the post because it is wrong/contradicts my existing knowledge/is worded insultingly’.

There seems to be a general agreement that people should avoid communities that promote misinformation instead of downvoting it as well, which I find contradicts the idea of downvoting misinformation being a purpose.