Downvoters have no obligation to comment but Moderators, being in a somewhat more responsible position than an average user, should atleast try to leave a comment on the action they take on user's flags.
I flagged a (plagiarized) answer recently and it was deemed invalid. Aren't there ethics of ensuring that proper sources are cited, specially when the answer in full (including the prefunctory wisecrack) is a
ctrl v of an existing thread on the internet.
I am sorry but Meta-contributions to this website are beginning to seem impossibly unwieldy for a new user such as me. "Invalidations" left without comment by the deciding moderator dont help the cause. I have benefited a lot from this website, and I try to contribute by upvoting good questions\answers; today I tried raising the flag when an obviously copied answer had been posted. Such reaction on the behalf of the moderators is really a slap in the face of even a meager attempt on my part.