This is a vacuous statement. No one is stopping me from using JPEG XL in the same sense that no one is stopping me from using DIMG10K, a format I just invented. But if I attempt to use either of these in my website today, Chrome will not render them.

In a very real sense Google is currently stopping web authors from using JPEG XL.

The web was designed from the start to solve this problem and you can serve alternate formats to user agents which will select the one they support.

Your statement here amounts to “you can serve JPEG XL to other browsers, just not Chrome”.

Yeah, that’s what I said.

Okay. So putting it together…

If the user agent does not support JPEG XL, then you cannot use it.

“Nobody is stopping you from using jpegxl” except Google.

Then what is this article about?

It's a meta-commentary about the death of critical thinking and the ease with which mindless mobs can be whipped.

From the jump, the article commits a logical error, suggesting that Google killed jpegxl because it favors avif, which is "homegrown". jpegxl, of course, was also written by Google, so this sentence isn't even internally consistent.