I don't know about 50+ who code together. But if you're interested in a community for old folks who enjoy reading computing stuff together, there is a small and cozy reading lounge on IRC (and Matrix) here: https://bitwise.codeberg.page/
2 years ago I created a private slack and invited a bunch of old colleagues (in both senses), we now meet weekly to hack on side projects, participate in CTFs, all low expectations. Sometimes we just catchup and bitch about work.
I assume you know about 2600?
Its a very fun and global hacker community, with monthly meetings, yearly conferences, a radio show, and great magazine. 2600.com
It's not that simple. Depending on the culture, interacting with people of drastically different ages can be uncomfortable for all involved. If you add the general lack of soft skills among programmers, it's easy to see why someone would prefer a "safer" group that's closer to their age over the more general community.
Let those people have their groups, fine. But there's no rule saying you have to cater to them. There's all kinds of people including people who enjoy going out of their comfort zone and experiencing "danger."