People certainly do have loans and deposits at the same bank.
I don't owe money now but at one time I owed a bank $70,000 for a home loan, and at the same time had deposits in various accounts, a vehicle loan, a business loan, and indeed an account for the $70,000 house loan.
You are right about the importance of the loan-deposit ratio...but that doesn't prevent a customer from being both a borrower and a depositor.
I, too, have deposits at the same bank I have a loan, but I DON’T HAVE THE EQUIVALENT DEPOSIT OF MY LOAN, THERE.
That is what the author is saying, and it’s wrong, and you don’t see it.