Most people that really believe in the site will invest regardless of what reasoning/data you provide.

For example, say you buy 10000 KHS.  It's reflected in your account by the next 10 minute interval and you get a reward.  Then that reward stays mostly the same with some variation.

If real mining was happening, your reward would take time to post and vary based on share validity of the mining.  Not to mention that mined coins need to be converted to Bitcoin.  

A real cloud miner pays a reward based on the actual performance of the hashpower.

The justifications you hear for Scrypt.cc's almost immediate payouts, like that admin mined with the KHS himself before selling it, are laughable.  

But these kind of basics of mining are lost on the ones that really believe.  They have some weird dogmatic commitment to scrypt.cc.