People saying "It's not that deep"

It seems like most people I hear say this do so to avoid justifying their own poor logic or decisions. Just today, I had a coworker make planning choices that were incredibly illogical and inefficient and resulted in making me take extra time to do extra work. When I asked him what the logic was behind his choices, he gave some pathetic reasoning that I asked him to clarify/expound on. All he could say was "it's not that deep". I asked why not, and he just kept stammering out bullcrap.

Like, holy frick, just accept that you were wrong and made a dumb choice, apologize for throwing off my schedule and causing me extra work, and learn from your mistake so you don't do it again. It's okay to have made a mistake as long as you accept that you did.

This is not an isolated incident btw, I've had many experiences with people who know they aren't operating on logic, so they just use "it's not that deep" as if that makes it okay