Maybe you’re missing the context of who Gary Marcus is

A blog is an opinion piece. The subject of interest, Sam Altman, is a public figure and CEO of one of the fastest growing tech companies. He's testified in front of Congress on AI regulation and has a lot of pull and influence on regulators. Some of the things and actions he's taken in the past are controversial, thus, thinkpieces get written. The AI industry is quickly en route to trillion dollar plus territory (already there if you count Nvidia as an AI company). There's a lot of money and emotions at stake for the AI gold rush. When someone is at the forefront of these types of things, like other public business figures with controversial tactics (Musk, Gates, Jobs, Kalanick, etc) it draws attention.

Well, sama managed to convince a lot of people to give his company billions, is making apocalyptic predictions that some CEOs take seriously etc. Making sure people at large realize the guy has a very loose relationship with truth, for many years, seems like public service. It's only libel if you spread false statements which Marcus is careful not to make.

> You regularly make personal attacks against individuals on the internet?

Isn't that basically the history of the internet?