First, I am not sure which exact statement was made. Also, you cannot just say "without CF" because you are essentially creating an artificial market with messed-up utility. In summary the cheapest-to-deliver bond is:
The bond that results in the smallest loss or greatest profit for the futures seller.
Futures sellers have to buy the bonds they are going to deliver against the contract. So, it is the bond with the lowest price relative to the invoice price. You see, you do not get around applying conversion factors if you really want to figure out the CTD bond. There is no "CFD do not apply here" type of argument.
But to come to your question, to say "It states that without CF (conversion factor) the CTD (cheapest to deliver) would be the bond with the longest maturity and highest coupon." is definitely incorrect. I highly doubt this is what Fabozzi ever said, either it was a very bad typo or you misunderstood.