If he WAS speaking as if he were a beneficiary of Disney profits, wouldn't he be encouraging the seating of cash-paying customers, seeing that WDW would see revenue from the DDP already purchased (whether they eat or not) PLUS the money from the cash-paying guest?
That being said, I agree with your main point. There's nothing about DDP that gives you certain rights at any particular restaurant. DDP gives you the right to 6 FS meals for a 6 night stay. It does NOT give you the right to "Friday night, 7:00 PM, Mama Melrose's, Saturday night, 6:15 PM, Rose & Crown." Regardless of your method of payment for meals, Disney is VERY clear that ADR's are STRONGLY recommended. DDP or not, failure to abide by this warning means you don't get the best choices for meals. There's no reason for a DDP guest to get preference over a cash-paying guest either for making ADRs or walk-in service.