My money is them being 99% scammers who don't have whatever they claim to sell and are just looking for idiots to send some money - and as with intentionally using spelling mistakes in scam mass-sent emails are intentionally used to help filter out people who might realise the Nigerian prince isn't real, it makes sense to look incompetent at doing the listings.

I wonder if any law enforcement agency (or researchers with an agency's permission) would / has ever do(be) a study of trying to buy from a large enough number of ads to know what % are scams vs. real.