The security holes created by Musk's rushed Twitter rebrand

Actually no. He lost control of the domain when x.com merged with Paypal, and even moreso when he no longer had any stake in paypal. He didn't regain ownership of the x.com domain name until 2017.

Journalists get mad about, say, Google changes and initiatives all the time. Twitter is one of the most influential and important websites in their field, and a hot topic all around (which is Musk's intention!) so of course they're going to scrutinize and report on it.

You just don't happen to see impulsive large changes like this with traditional tech companies very often. The Alphabet change springs to mind, but that seemed to have a lot more prep put into it, hence it was probably a bit harder to find interesting factoids or issues about it.