Bumper problems of the 2000 Toyota Toyota Truck

The rear center bumper of my 2000 Toyota forruner sr5 4 wheel drive is rusting. I noticed on many other 2000 forruners that there is also a rust problem , again only on the center bumper. Because of the amount of vehicles I observed rusting in the same location it appears to be a product defect and failure. I wrote to Toyota and called them, they said to bring it to my local dealer to look at the problem. They told me it was out of warrenty, but maybe they would chip in half for the repair. They completely wasted my time, as after I wasted a half day bringing it over, they acknowleged the rust wasnt from damage, but they would do nothing as it was out of warrenty. I told them then why was I told to bring it over to look at and waste my time. They did not give me a valid answer. I have seen at least 5 other vehicles like mine.