However why this 1xbit spammers are saying KYC casino is good? what I know 1xbit is a casino that doesn't require KYC, so does this mean 1xbit is a bad casino? 
This is quite smart and would be possible. It would be interesting to see how the casinos would battle an influx of fake documents... This would most likely create another completely opposite industry (e.g. software to detect fake documents).
There's no tools that has a perfect system to distinguish between fake documents and legit documents, those tools only give a percentage of possible the documents got edited. False positive could happen, it would make a genuine gambler got accused, this is why requiring KYC is pointless.If a gambler decided on what he wants, define his search and go after it, there's nothing bad about that, KYC is nit a thing of force to do, it has to be an optional decision to take and the extent to how you can research and trust the findings from your search is what should be considered, but we need to emphasize that casinos need not to frame things up about their KYC requirements before gamblers to engage them and later regret their decision in choosing them, which means there must be transparency in whatsoever thing we do.