Most of the people live in the world they invented, where they are the protagonist, naturally young girls want to talk to the protagonist, even when he's 70. You'd have to dismantle their whole worldview to disabuse them of the protagonist idea, but by 70 it's often too far gone and requires facing a million mistakes they have conveniently swept under the rug with the fairytale they've told themselves.
I recently saw a screenshot from Facebook of a mattress ad presented inline in a page load that had two conventionally attractive normal looking (fully clothed, not immodest at all) women on a mattress. Below it was somebody's grandpa writing a message basically to the effect of "hello sexy ladies I am (name) please chat with me".
It possibly could have been a bot, but I don't think bots commonly use profile pictures of dishevelled looking 75 year old men. Maybe for commenting on political agitprop, they do...
At that age a lot of people literally don't have the intellectual capacity to deal with this. Their brain is biologically atrophied due to illness, not exercising it anymore, not seeing or hearing well anymore (this has a huge impact), being socially isolated, etc.
They're not inventing a new world, they're not "conveniently" and consciously sweeping anything under the rug, they're not telling themselves a fairy tale. They're just losing much of the world they were living in and have to deal with what's left, holes and all. Why do you think old people are such easy targets for scams and fraud in general? Do you think only the body degrades with age?
If you're young enough to not have seen this in action ever, you'd be excused for not understanding at all what happens and for building such bad faith scenarios. Common sense and some light reading on the topic would have prevented that nonetheless.