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.
Most A/B tests are experiments on features, not on their users.
There’s a difference in finding out what features users likes and let’s see if we can manipulate their feelings or get them depressed.
The one Facebook did is not really A/B feature testing.
Those who opt-in to tests can have biased results, it’s like asking those running Windows 11 if they like Windows 11 more than Windows 10.