When I pen test PHP custom-built sites, I almost always find a dozen high-severity security defects.
Many of the popular PHP-MySql tutorials on the web have sql injection bugs, not a good way to learn a new language.
Not saying PHP is secure by any means, but it can be implemented securely - it just isn't very often.
That said, if there is an argument to be made for PHP, i'm afraid to say, I don't think the linked article does a good job of making it. While I think its suggestion that PHP has evolved beyond some of the common criticisms against it might have merit, it doesn't address that the bulk of PHP code in the wild most definitely has not.
PHP is evolving, many sites on the web are too. But legacy codebases are here to stay, I mean look at how many sites are still on classic ASP.
PHP was one of my first programming languages so I will defend it, the ecosystem is much cleaner than it was a few years ago, and it's still the easiest to deploy language IMO.