The morals are also different too. Some people might not like eFreedom, but the fact is that StackOverflow is CC-BY-SA. Anybody who wants to repackage StackOverflow content in a different way is free to do that. I do think that StackOverflow should generally outrank eFreedom, but a site like eFreedom can potentially add value a lot of value.
On the other hand, other spam sites are generating original crap content with their own crap content generation system... And if they aren't, they can switch to some other content generation method to get around duplicate content filtering.
(And speaking of which, duplicate content filtering content of some kind is absolutely essential for a workable web search engine... It's not even a matter of spam. Building a search engine for one the largest units of a large Uni, we found that there were many documents that were duplicated all over the place for all sorts of reasons, and that since the on-page factors are the same, these tend to form 'plugs' of search results that displace other results.)