Holly, I've lived in a 55 plus active retirement community for 16 years, and love it. It's not perfect, of course. No place is. I think most of this guy's dire warnings were facile nonsense, with a tiny sprinkling of truth for some communities, I guess.
Listing problems such as busybody neighbors, community rules and restrictions, the fact that some neighbors may be cliquei-ish or catty, and the inflation of HOA costs (along with inflation in everything else, no matter where you live) is just a facile way of appearing to tell us something we do not already know. But most people in our age bracket already know those things, and they apply wherever we live.
In my own real life experience, we have a normal variety of personality types, the same as everywhere. Some people are saintly, some are brilliant, some are dumb, and some are nuts. Some are nice, some aren't. People don't magically change just because they've lived a certain number of years. This building is a friendly group with umpteen activities for those who want to be friendly.
There is a preponderance of moderate liberalism, and politics is important, especially in the current time. So political extremism is something that probably does factor in, in some communities and for some people. But wouldn't that be true if you are just moving to a new area, regardless of the age of the residents? Most of us like to live among similarly minded people.
We do have children and young adults visiting here, all the time. Not everybody is "old." And people in their 50's are not old, anyway.
Size of pets allowed can be an important restriction. When we moved here, we had to give our golden retriever (Sunny) away to a friend who kindly adopted her. The size limit for dogs was about 30 pounds or less, and Sunny was about 70 pounds! She would have hated it here anyway; apartment living is not for active retrievers who love dashing around the woods. And I think there is a limit of one dog or cat, not sure about that.
In general, anyone can say the bottle is half full or half empty. I had one friend who had been generally depressed and complaining a lot, whom I had known since we were in our 30's. She was always like that. She and her husband moved here when they got older, and predictably, they never liked it here very much. They ended up moving out of state to live with a daughter. I think those who engage in all these complaints have probably been complainers all their lives.
So, while this guy raised mainly valid points, they are pretty much on the level of "Be careful crossing the street."