Just an observation. In a developing country anyone with better academic performance is compelled to pursue fields that pay well. So that statistically skews the other fields to people of lower academic performance up to high school. Academic performance correlates to cognitive abilities.

STEM grads I see around me have no problem with communication or anything a humanities degree claims to "teach". I think it all boils down to people and their cognitive abilities.

Second factor is subjectiveness of humanities fields; in STEM fields there are often objective measurements. It's much easier to bullshit your way to and through a non-STEM degree, especially when you have money and background.

Edit: I have heard "humanities" as solution to engineers not writing proper docs or bug reports. That is missing the real reason, which is pretty boring. We don't have conceptual foundations of many things we use. Fresh grads even more so, due to abysmal education system.