Not sure if it's statistically valid or what, but anecdotally the loudest "older people" are the kind who start and end every conversation with "Ugh, kids these days! Am I right?! Back in our day, bla, bla, bla..." I believe this sort of thing does make people think the geezers might be somewhat out of touch with the present.
Generally, this is just an attribute of traditionalist society. According to it, only older people can be president (for youngins don't have the requisite "wisdom"), women should choose family over career or the necessity for the older people to shit all over the "youngsters today".
edit:
Let me elaborate. My central point is that traditions rule in traditionalist society and generations dismissing each other is not unique to programming community. I did want to add that to change the status quo guys like the OP must outshout the more traditionalist voices, but I thought that was self-explanatory.
An example of the latter is Emile Ratelband [0] who argues he shouldn't be held back by traditionalist assumptions about his abilities due to his age. I support the man.
[0] https://www.npr.org/2018/11/08/665592537/69-year-old-dutch-m...