Haha, you would think that but actually they do. I laugh because I'm an Iowa fan (obviously) and it took some time to get used to Norm Parker's philosophy on defense. I remember scratching my head when he would leave his 4-3 group in to defend against spread sets and then seeing that it could actually work.
I realize that's not your main point and just because one or a couple teams do it doesn't make it "normal", but it's not out of character if you saw it during one or two games.
Keep playing and you'll see differences.