Yes, that thread is in our Political News forum, and users are required to have 100 posts and have been a member for six months in order to be able to post on those threads. There's a note at the bottom of affected articles mentioning the restriction.
We know there are plenty of users who could make meaningful contributions to these threads but don't yet qualify to post there, but experience has taught us that the restriction significantly reduces the amount of hit-and-run trolling on controversial topics, so it's a trade-off we've elected to make.