He also seems to have very surface level ideas about risk-reward matrices, and how these change based on various factors. Someone else in this thread already mentioned this briefly.
One of the core tenets of classical game theory is that different strategies a player can use will have different rewards (payouts) attached to them, these being contingent on what the other player does. This applies to football as well. Let's assume that going all-out attack and parking the bus are two extreme ends of a spectrum of possible strategies a manager can use. In that case, all possible strategies will yield different payouts (and entail different risks) depending on the circumstances of a given match. These include what the opposing manager chooses as his strategy at a given point, balance of power between two squads, scoreline, time left, and many potential others. If you're taking a risk, it needs to be a calculated one that can be justified by some of those aforementioned circumstances. Same goes for avoiding a risk.
Not sure if I'm doing him injustice, but it seems like he thinks that all these calculations are beneath him. He can't be bothered about all these variables and how they can possibly affect the validity of different strategies. Using game theoretical language, he just believes in a dominant strategy of attacking, front-foot,risk prone football (closer to 'all-out attack' end mentioned above) that is guaranteed to yield the best possible payout in any given situation.
If the game in question involves such a lopsided balance of power that one player is guaranteed to win no matter what, he can indeed get away with a dominant, uncompromising strategy. That's what Ange sounds like when he talks about how he'll play the same way regardless of score, opponent, time, weather or anything else. He's advocating for a dominant strategy that he thinks is also applicable to this league and this club.
This premise of his is highly questionable though. To the extent that the game in question is not as lopsided, you need to take many other factors into account in deciding what you're going to do. All that aforementioned bravado won't cut it. Hence the criticism of "He can only do it with Celtic in SPL!!"