>but would just stifle low effort downvotes

With the exception of spam, that's a feature. If something offends you, you should consider why.

Upvotes are useful in reducing spam, as without them, I'd have to repeat a sentiment to show agreement. In my experience (anecdata warning!) that nicely leads to both the best post for an argument, and the best rebuttal, sharing visibility.

Neither combat the problem of "fake news", because frauds don't have to be well done if the local community agrees with the sentiment.