Not sure Blender is the problem here. People looking for that quick buck would just turn to pirated software in any case. As previous poster said, Blender has become a big thing, and a lot of indies, who may later go on to commercial software, often start there. In my experience, indie customers far, far outweigh commercial organisations. I've started recently offering Blender format alongside my other formats, and this has proven a good thing.
As for moderation ... I've worked on sites which have had heavy moderation, and it is much more of a pain in the arse then you might think. Not only is there a huge delay to get published, often there are rejections for completely invalid reasons which then need to be chased and overturned. I get it, the moderators are busy and need to rush things through, and with so many different formats out there, they can't be experts in everything. Not to mention the incredible workload this adds to the site. It's enough of a hassle having to email CGT every few months to ask them to "approve" my low poly models.
To be honest, I see the hands off approach at CGT as one of its strong points, from a sellers point of view in any case, but I appreciate this will increase the likelihood of customers getting defective products. Sellers putting up defective products don't last in the long term, but I'm not sure what's the best short term answer; surely you can get a refund for a product that is defective, and buyers should get clued in by the sellers rating, reviews, etc. Dunno.