Why worry what anybody else is doing?
Besides, many pros use P mode, Joe Buissink is a $10,000+ wedding shooter and he only ever uses P mode.
Agreed. The whole debate over "P," "M" etc., is the stupidest thing ever. They all get you to the same point (or at least they should if you know what you are doing). It's just a question of where you want to start out. All a matter of personal preference and one's choice for a starting point doesn't make you a worse or better photographer.
IF you know what you're doing is key in any situation, he clearly did not.
Besides I know a few pro-shooters that has absolutely no idea about how to improve their technique and doesn't how to use a camera to their advantage. I have helped a few with their 5d3's and 1dx's with things that annoyed the hell out of them and they found some crazy workaround that is totally not necessary. Not that that must be the case always. But if it looks like a monkey and smells and acts like a monkey, it surprisingly often is a monkey...