I recently received a downvote without comment on a question and all of its answers, which are good independent of the value of my question imo. I’ve also had two other questions receive similar singular downvotes with the (good) answer on the latter question also downvoted.
I had written all this off as unfortunate but necessary byproducts of anonymity, however the discussion in the comments here raised my eyebrows — it seems that this recent phenomenon is not isolated to my posts.
I’m not entirely sure what to propose we do about this, if it is one individual or a small group of them. I agree that anonymity in down voting is essential and it would be burdensome to have to put in an explicit reason each time we downvote, but it seems generally discouraging to the spirit fostered on MO to have unexplained (and apparently unjustified) downvotes unchecked and on the rise.