This is certainly an extreme example, but I feel that most designers believe (and their management expects) in these sorts of design decision justifications. Designers need to sell their designs, and a large majority of the time there isn't enough actual thought to justify anything; it's just preference, or at the end of the day, there are lots of good enough solutions.

There is a significant problem in the design of performative work that provides little to no value. So much time is spent on "process" and "workshops" that yield nothing, yet design management rewards it. I've informally polled peers of designers, and the common view is that, depending on the designer, only 20-60% of what they do is of any actual value. I think the state of the design market reflects this. Designers need to engage in serious introspection and figure out which parts of their work are valuable and which are not. The industry has been discussing "proving our value" and "getting a seat at the table" for years. If we've been working on this for 15+ years but haven't achieved it, I think that shows something about the actual value design provides.

Source: I've worked as a product designer for 10+ years.