I agree, people think that you need to show proof of your birth certificate or something to play, it is a simple verification that you pass and its fine. I guess it is the fear that one day yo ucould be asked and this could have some governmental backing that will put you in trouble that makes them stay away from the place. I am fine with it because for me it is not illegal, I mean it technically could be, but I am not playing with "real" money based on our laws, hence it is not technically gambling. Laws here see this place, same as playing those slot games on your phone with game tokens, hence I am not worried about KYC anymore, I disliked even hated the decision to ask it, but I got used to it.
there are many minors who are playing and for this reason they do not like KYC, there are many people who do not have their own home and who are still at their parents' house even though they are minors and for this reason there is no way to deliver proof of residence because the water, electricity and internet bill is not in their name,
there are many people who are afraid to hand over their passport on a strange website. That's why KYC is a big headache for most people, especially when we know that many casinos have anonymous owners so it wouldn't be fair for an anonymous casino to ask their customers for KYC.
The KYC procedure is performed by a third-party service provider, let's not forget about that. The site itself doesn't need your personal details. They just have to comply with the law requiring for their users to pass KYC.
Also, as far as I know, the collected data are kept encrypted, and no human being actually reads them, I even heard that the data is then destroyed to avoid any risk of leakage, but I'm not sure after what period of time this happens.