It's not a brag. It's just a statement that it's possible to plan your campaigns where you don't face shortages. It's just simple things like only attacking with tanks, having green air, whatever, that lead to you taking minimal casualties. What's the point in bragging about something I don't consider to be anything special, and playing a campaign smartly and not taking massive casualties isn't something to be proud of, it's just normal. Just relax and take a joke, man. No need to read too much into it.
EDIT: Note that I didn't say I never have scarcity of anything, just that if I put myself in a position to need to fight in multiple theaters, I make sure I'm prepared first. If I'm facing shortages I'm not going to be opening up a second front somewhere, or trying to commit to defending somewhere across the globe.