Why requeue isn't available in Twitter?

This is why Tweets can't be requeued.

Twitter strictly forbids reposting of the same content on its network. For that reason, we've disabled ReQueues for Twitter only, it works on Facebook, Instagram, and LinkedIn. You can still go to the Sent folder and open the message you want to resend 'as a copy', then make a change to it, then add it back to the Queue just over the Twitter profile. Another requirement they've imposed recently is that you can't include more than one Twitter profile in a single post, so those have to be done in the same manner as described above, one at a time.

Please be sure to make some change before reposting content, as Twitter can shut down accounts with no warning or recourse if you violate these rules.

👆 You’re all caught up