That's not really a solid argument to me. No part of the original post or the followup helps me understand why he thinks a former lobbyist for Amazon and Google would be for anti-trust action against them.
Most of the responses on reddit, while overblown, are generally pointing out that most of big tech was funding Trump and Vance's election. If most of the CEO's argument is how much the democrats are in the pocket of big tech, that seems quite relevant. A pretty substantial percentage of the money spent to elect Trump was from Musk and other VC folks, and Bezos notably killed an endorsement of Harris at the newspaper he ran.
As someone said in the thread, it feels like the CEO took a "the enemy of my enemy must be better" in this, when it's entirely correct that both US parties are in the pocket of corporate interests. He's not wrong about the Democrats, but that definitely doesn't mean Trump's appointments are better. He could have just decided to sit this out and say nothing, which makes it all the more objectionable that he decided this was his time to show up and publicly try to get Trump's attention to praise him. As far as I know he wasn't @ mentioning Biden to praise the various anti-trust actions that were taken over the last few years.