The sane or lazy choice? Right tool, right job; would be the right choice.

Wrong. When you have dozens of systems to manage that can all have security vulnerabilities, the less burden involved in keeping everything up to date and secure. Uniqueness breeds unique and unforeseen problems. (The modern way to describe this is to make servers like cattle, not pets.)

In a Windows environment, the best tool for the job is almost always another Windows box. Arguably, sure, PHP is a poor choice for a Windows environment, but IT/operations rarely has the luxury of deciding what line of business apps other departments use.

thats certainly one point of view. i would still call it lazy though.