In the last 3 or 4 weeks there are quite a lot of sandbox proposals being downvoted. A quick count in the first page reveals that 12 proposals are at -1 and 2 are at -2, and some of the -1s are neighboring proposals in terms of active time.
After several days of monitoring, I found that most of the downvoted proposals (including 2 of mine, I'd say) were downvoted only after several days of posting, and most if not all of them received no comments and upvotes during the first several days. On the other hand, if a proposal has upvotes, there will be almost no downvotes (except the Mountain Range Numbers one, which was -1 before posting to main and received upvotes in both main and sandbox afterwards.)
Moreover, the downvotes are, in my honest opinion, unattested without reason. This dampens the intent to post challenges, which could post a devastating threat to the site's health because the downvote may bring a negative meaning like the proposal is not suitable to be posted, etc (at least I basically won't post a challenge if the net vote is negative.)
So I basically would like to know what happened to the downvotes, and what we could do against those downvote floods.