First off, lol if you think Reddit wasn't full of politics every bit as much if not more than Facebook.
Second, what's happening is the opposite. The older users, the ones that remember a pre-facebook internet, the ones that are not pre-programmed to accept whatever the app in the app store tell them, they are the ones leaving.
The young are actually increasing on Reddit because it's pandering to less tech literate, more TikTok-focused userbase now with the official app. The type of users that need algorithms to tell them what to do because they've long since failed to learn to actually use technology smartly.
The type of user that was shocked to learn there was such a thing a third party app.
Those are what reddit wants, and it's what they'll get.