If it is all misinformation and I want to reduce its visibility, why does volume of down votes matter?
I mean the whole idea of 'down voting too much' is that the down votes, which are basically instant after reading a post or comment, are done in a short period of time. If someone takes a few minutes to browse a community to see if maybe a couple of the terrible posts are outliers and vote as they go, is that really any different than down voting them when they are noticed coming through a feed organically?
Note that nobody cares about the frequency of up votes.
If there is no point because it won't be seen then there would be no negative impact from the downvotes, and punishing someone for downvoting 'old' misinformation would be silly.
I downvote misinformation because if someone comes across the community later they are going to see those old posts too. Same reason for downvoting a 5 minute old post as it would for a 5 day old post, misinformation is misinformation.
Why isn't upvoting spam? I have upvoted 10 times as many comments as downvoted, and hundreds of times as many upvotes for posts as comments. Is that spam?
But then you proceed to downvote every post in the community. That's where you went wrong. You should have realised that you'll likley disagree with almost anything posted there and should have just blocked it.