that may be for a lot of reasons, but I would argue that the idea that older adults like old candidates because they are old, which seems to have been what you were arguing, is false or at least pretty weakly true. If anything older adults have the same skepticism about an old candidate as anyone else would, and look for the same kinds of evidence pro or con about a candidate's capacity as anyone else, and may actually have a sharper eye for recognition of signs of deficits.