It does not say to enter any Ethereum private key.
It is for creating new wallet for Beacon.
I am interested to see developers reaction to your claims.
They are very inactive in every way.... and not present in social media also...
For me as @morvillz7z posted above, It require you use Keystone + password or Private Key to access the wallet. It's mean they have your wallet, so don't be scammed like this bro.