The issue is detection: once you know they are zombies, their actions are not hard to undo.
Generally true, but with Reddit code and Reddit database schema, everything is hard (both detecting the zombies and undoing their actions). One of the reasons to move to LessWrong 2.0.
(This may be difficult to believe until you really try do download the Reddit/LW codebase and try to make it run on your home machine.)
If it's worth saying, but not worth its own post, then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should start on Monday, and end on Sunday.
4. Unflag the two options "Notify me of new top level comments on this article" and "