If you read the comment for more than half a second you'd see they're not questioning why someone would use PHP. They're asking why you would use this particular server over nginx/apache, given how robust their support is.

Signed, a PHP developer.

They are asking about why would you need an alternate system? What is the technical reason behind it? What’s the disadvantage in the current system? All while acknowledging that they used to work in PHP and haven’t recently so they understand a lot less.