Apple nearly killed Tumblr over accidental third-party CSAM. Them not doing shit about Twitter[0] is complicity in my book.
As for the political content of this article, I would argue that Trump is a lot less powerful than John Gruber thinks. Certainly, Big Tech knew how to shut him up when he was doing an actual self-coup. What changed between Trump I and II is that the liberal establishment saw this act and realized they'd let Big Tech get away with murder. Antitrust is Big Tech's existential threat, and that's a power Trump absolutely does wield.
Of course, Trump is not the only person wielding this power. The EU, Japan, and other countries are passing laws to strip Apple of their power to control apps. So they need Trump to use US trade policy - the biggest lever we have[1] - to beat the EU into compliance with Apple's rules.
There's an additional wrinkle in this story, though. Musk isn't actually favored by Trump anymore. He was a Trotsky - useful to the Trump regime's ascendance to power but not necessary now that it's in place. I don't think Trump is actually defending Twitter from Apple's actions so much as this has always been the limit of Apple's power.
Going back to Tumblr, there's a reason Apple went after them. They were small, and easy to bully. For all Apple's grandstanding about "privacy is a human right", the only thing they did to stop, say, Facebook[0] was take away IDFAs. Facebook has blatantly violated Apple's guidelines time and time again, up to and including shipping ad tracking VPNs using Enterprise signing certs, which is extremely forbidden by Apple policy. If you or me did this, we'd be so blacklisted from writing iOS code we wouldn't even be able to open Swift Playgrounds on an iPad. And all this happened before Trump II figured out how to threaten the economy into compliance.
Twitter has shrunk from what they were pre-Musk, but they're still big enough that they can pay the third world to tell Americans why America should kill people who live in the third world. An iPhone that can't Tweet is materially worse, so Apple is going to let Twitter get away with murder (or, more specifically, trafficking CSAM). If you're big enough, the laws do not apply.
[0] It is always ethical to deadname corporations.
[1] This is literally the stick we used to copypaste DMCA 1201 into the local law of basically every country, over the objections of everyone including Americans!