I avoid registering at instances that have downvotes disabled. In fact I specifically joined lemmy.zip based on it having downvotes enabled. My question to you is why did you join lemmy.zip knowing that downvotes are enabled? You can see that downvotes are enabled before you make an account here :P

Can’t speak for everyone but for me I rarely actually downvote unless it’s someone doing obvious trolling/baiting. And usually when I see posts in the negative it’s basically a warning not to bother clicking the post.