I appreciate your research. Now we know some people wasted their time/resource.
I think OP bought this wallet on that site and got tired to brute force it so that's why he gave it away the wallet.dat
There are some group which distribute wallet.dat either for free or swap different wallet.dat, so it's also possible OP didn't bought it. But if he do, let's hope this claim is true

We guarantee balance in the wallet. Otherwise, we will give you money back till 48h!
I didn't know that wallet.dat file with lost passwords can be sold lol..
It's more common thank you think, although there aren't many wallet.dat seller here since another member would quickly give negative feedback and say the seller is scammer.