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.