If you're not constantly working with linear algebra, you're going to get rusty fast. Mind you, he seems like he writes a matrix multiplication with goto based loops every time, so he can make sure that he keeps knowing linear algebra, and to prevent the business he's working at from getting anything done because he doesn't like their ethics
Sub par developers parrot industry recommendations such as code reviews or microservices, and Above Average anti-social dude asks why and gets a dumb answer, and out-engineers all the idiots trying to mimic industry best practices.
Now Above Average engineer’s ego expands even more. Not only is he smarter than everyone else, all these best practices are dumb too.
Look at all these people needing code reviews or unit tests, they still can’t ship. Those people doing it at Meta and Amazon must be dumb too.” They think.
The thing is, their arrogance and/or disdain for (whatever) endures they only get hired at companies where this cycle repeats.
It is not a “brag” to say none of the developers you’ve ever worked with don’t understand linear algebra, it means you only work with morons. Being the king of morons isn’t a thing to be proud of…
Edit: oh God, I looked at his linked personal site and this isn't a parody account. I really hope this guy is drinking or something, he claims to have worked in VR/AR. Claiming that none of his coworkers in 20 years have been able to understand linear algebra, while working in that field?