Some dogs are not into food so much.
I also was told no more flirt pole as he was too interested/reactive in everything else that was moving.
Why is your trainer squashing his enthusiasm? I'd want my dog to show interest in an object if the food isn't getting it. Ball or tug on a string is a great training tool for young dogs.
Where I train the flirtpole is utilized often. Food is used for certain exercises and the prey rewards are used to engage.
Don't get discouraged, change up your training!