Whoa! Should’ve mentioned this image contains a spoiler!!

It looks like the limit is on reading posts, not posting itself. It’s way easier to read that many posts, especially if you’re glued to your phone and scrolling past dozens of uninteresting tweets at a time.

That being said, this limit is likely in place to stop web scraping or some such workaround to the need-an-account-to-view-stuff policy.