I don't disagree with that. But on this board, any team that runs I formation is considered "pro style". When pro teams rarely line up in any 21 personnel sets. 11 and 12 are the most common, followed by 10 and then 21.
I also get annoyed with the belief that you have to play under center to be "pro style". Which is probably done on less than 50% of snaps now in the NFL.
But I do agree that a big issue comes from the ambiguous definition of "pro style". I'd say the best definition is a running scheme based around either zone or power and counter schemes (like the Redskins under Gibbs), with either a vertical Air Coryell passing attack or a quicker west coast attack.
Which is why CBJs offense is 100% pro style. He uses zone, power, and counter run schemes with a west coast passing attack and a ton of 11 personnel.