I think Kendrick either declined to perform or couldn't make it. Originally it was only going to be Shallow and All the Stars that were performed.
Sounds like a face-saving way of saying "Kendrick told us no" to me. He also declined to appear at the Grammys this year.
Say what you will about the rest of his post but it's very cool to see Bo Burnham's name listed with the rest of those guys
Of all of the things to file anti-trust against. Justice Department Warns Academy: New Oscar Rules 'May Raise Antitrust Concerns'