Forking content happens all the time to Wikia, Shoutwiki, Mirror sites, etc. Of course its best if Wikipedia is credited, but with the open source licensing of Wikipedia's content, its not required as far as I know.

 

Another angle to look at for why these folks no longer edit would be how their content was reverted. Was it reverted because it was wrong? Because some article owner showed up and had a different opinion of the article? Did they leave a snide comment or call it vandalism, cruft, spam, trolling or some other derogatory term often used on Wikipedia? All these things matter when it comes to our impression on new editors. The reality is that it takes time to learn to edit. Wikipedia has hundreds of policies and thousands of essays clarifying them, even well established editors and admins often disagree on what the right interpretation is (hence the arguable need for the Arbcom). Arbcom rarely deals with new editor problems, they deal with established editor and admin problems, so to assume that editors only leave because they don't understand or aren't qualified to edit is, IMO, under-representative of the larger problem in Wikipedia of trust, helpfulness, abusiveness towards editors (particularly new ones), article ownership and bad faith assumptions.

 

Reguyla