I guess age and anger make assholes of a lot of us, eh?
Yes. At least a little cranky at times.
My best guess is age brings pain, either physical and/or mental. Constant pain, even if relatively minor aches, can make people cranky.
The psychological pain is seen in a lot of the Trumpers; they are angry and bitter. Why? It's not that they really give a shit about "We, the People" or the Constitution as proved by their own posts seeking to strip Americans of their rights. They just use that as an excuse for their bad behavior. IMO, it could be regrets over life failures and mistakes or it could be mental deterioration such as dementia and paranoia.
In conservative men, it's common to have the highest respect for the "manly men"*. The weak ones seek to bully and attack those they perceive as weaker in order to enhance their manliness. The American male version of a chicken pecking order. IMO, it's a main cause of homophobic behavior.
As men age, they grow weaker and that pisses off the weak-minded ones making them bitter and angry. Having a touch of dementia, or normal age-related forgetfulness coupled with a little paranoia, just makes them angrier. Being weak in both mind and body, instead of accepting their fate and
taking it like a man, they wimp out and blame others for their problems. Hence, hateful lies and attacks on those who disagree with them. They demonize the Left, minorities and women as the cause of their problems.
*Martin Mull's Men song points out this perspective: