I haven't ever had blockchain.com, but I guess that it keeps your private keys on their database. How's that non-custodian?
I too have not used the wallet before, I downloaded it just to know how the wallet was at the time, and I deleted it without using it. According to the claim by the article I have found out about the wallet which I am not sure if it is true:
We do not store your bitcoins, we only provide you with the software you need to store them yourself. Your wallet is encrypted on your device with your personal password.
So, I do not think they store anything on the database.