As quoted from the linked post.
It looks like you’re part of one of our experiments. The logged-in mobile web experience is currently unavailable for a portion of users. To access the site you can log on via desktop, the mobile apps, or wait for the experiment to conclude.
This is separate from the API issue. This will actually BLOCK you from even viewing reddit on your phone without using the official app.
Archive.org link in case the post is removed.
ahahaha the reason I finally stopped using Yelp was because their mobile site would only load part of a review and would force redirect to their app if you tried to expand on any reviews. Rather than download the app or change user agent, I just gave up.
every website and their mother wants you to download their app nowadays.