Lets be honest here, the modern web is an over engineered fractal of bad design.
The language has made major changes to both syntax and functionality.
The very first specific thing mentioned in the article is "mysql_real_escape_string".
The mysql_ extension was deprecated in PHP 5.5.0 (released on 20 June 2013) and fully removed in PHP 7.0.0 (released on 3 December 2015).
I'm not going to bother rebuting all of it, those who really want to educate themselves can use Algolia search for the link and find great comments.
But from a quick glance of the start, the article cites "mysql_real_escape_string()". That function has been deprecated 11 years ago. And removed 8 years ago.
https://www.php.net/manual/en/function.mysql-real-escape-str...
It's kinda sad that the author doesn't bother to at least insert an alert. But I suspect that they enjoy the free traffic from people linking without this knowledge.
It's double sad that in our field we often strive to become more engineering and science like, yet many don't care to spread misinformation.
Also keep in mind: https://eev.ee/blog/2012/04/09/php-a-fractal-of-bad-design/