it is obvious isn't it?
there are sites for that too where you enter your private key to search the obviously fake "d-a-t-a-b-a-s-e" and obviously what that site does is instead of searching for it, it does a quick sweep to empty that address!
if you search OP had included a link to one of these stupid scamming method before!
i actually been playing around with this and i think i understand how its working..
basically, the page numbers generate fake keys.. they are all there tho.. but its not ones bitcoin core would generate..
you can generate a bitcoin address from any key starting with 5.. so just type in random numbers and you get a bitcoin address.. you can send coin to it.. but its not one that would be normally generated..
now, when you give the site YOUR key.. the site will use that key to unfake the list so to speak and show you a page with a bunch of random keys plus your own.. by changing the last few digits of your key.
i have no doubt this guy isnt recording those keys.. dont put your own in that you plan on using. i used vanitygen to generate a random one.
but more than likely every single address on this list will have a zero balance except the first few pages that someone has "tested to see if it works"