Sadly Reddit is locking down the personal finance subreddit behind their app so they can monetize it better. I find this article to have interesting timing as the readership on that subreddit must be going way down nowadays.
I must be in the bad A/B bucket because I see 'This community is available in the app' and haven't been able to use Reddit a lot on mobile for weeks / months?
Based on that article, I'm guessing this is only a thing in the new mobile site. There are a somewhat ridiculous number of ways to browse reddit these days (desktop new/old, mobile new/old, app at least) and they all seem to offer a different set of features. I've used i.reddit.com on mobile for many years now and it hasn't been impacted by any of the nonsense that reddit has been pushing lately (yet).
I know that if I spend extra time I can edit the URL but honestly this reddit block has allowed me to just stop browsing reddit unless absolutely necessary. A positive thing in a way...
I'm guessing you're on your phone? I get prompts urging me to use their app, but I have been able to opt for the browser instead, and I use Tor fairly frequently (phone and desktop). Have you tried old.reddit.com instead?
Maybe it's specifically targeting certain browsers/platforms. I'm on Firefox on Android, maybe they're specifically targeting iOS?