Personally I see it as a positive thing that these casino's ask for documents - it keeps the fraudsters at bay. However, I do think it is a little stoneage with the amount of information available to these companies online - they just don't want to pay the relevant fee's to obtain the information, thus making the process easier for players.
A simple example is what's known as a 'code 10 name & address check' - having previously worked for a finance department, these cost a company around $5 to run and it's a basic personal details check against the owner of the card. If they match, great, if they don't, there is reason to have suspicions on the account.
I do think these casino's should be doing more to make the process more fluent but it's as the old saying goes, if you have nothing to worry about then you have nothing to worry about!