I don't know all of what dang has said personally, but in most cases where I see new topics getting killed it's pretty obvious what the reasoning is; political ragebait, shady sources, plain junk articles or other low-quality threads.

The SDV/SKG petition thing was none of those, and people were generally positive about it during the discussion. So it seems to me it was either an unexplained random down-voting event or something a little more malicious.