Why do some students go entirely 3rd party, even at schools with a good preclinical curriculum?

Don't get me wrong, I love me some Sketchy / Bootcamp / FirstAid / Pathoma as pre-learning tools for lecture or to go over a confusing concept, and I'm using these materials more as I get closer to Step 1.

But I'm confused at the people who have used only 3rd party resources for all of preclinical years. At my school, it's mostly this one group of dudes. They are so vocal about how it's important to be "efficient" and how in-house lectures focus on "random minutiae" the professors think are important but won't be tested on Step. So, they "take the L" on in-house to focus on what "really matters."

It honestly strikes me as so arrogant. Yes, third party resources are designed to help boost board scores, and I'm sure these guys will do great on Step. But even though in-house materials have plenty of problems, there's so much clinically relevant stuff that's not on boards that is taught in class. Am I crazy for feeling like they're not seeing the big picture?

I know I'm at the very beginning of my medical career and I recognize that I have very little sense of what is important and what isn't. I also love hearing my professors (some of them attendings we'll rotate with in clinicals) talk about actual patients they help as physicians. But maybe I'm a dweeb for that.

<end of my self-righteous rant>