They're very prone, in my experience, to believing that their explanations are ultra-rational, though, reality be damned. And to falling for arguments with the trappings of rationality, but deeply flawed premises or early steps slyly skipped so the castle's built on sand but looks like a perfect castle with all these crazy-tall minarets reaching for the sky (ahem, like a certain popular-online political & economic philosophy) and then treating everyone who doesn't agree that the castle's beautiful as irrational, probably-emotion-driven morons.

And beyond this: engineers, particularly programmers, are particularly susceptible to flawed "first principles" thinking.

Not every factoid in every field can be derived from a small set of first principles, particularly when that field is primarily empirical in nature.

But many people are not rational in any part of their lives, so irrational arguments are not surprising from them. Some people don't actually know what a rational argument is - it's something that you learn in school, not something that is intuitive. They think that argumentation is when you make the other person shut up, rather than when you make a step by step case to get to a point from a set of agreed upon (at least provisionally) premises. You can recognize these people because they have a tell of repeating the same sentence over and over again to drown out the other person speaking. They're not trying to lay out a convincing case, they're trying to survive. If they trusted you, you could absolutely teach them argumentation and reason.

Engineers do know how to argue rationally, because they have to remember why things work to a pretty intense depth. The question is how people can wall off that ability instead of applying it to other things that are important to them.

Being "human" isn't an explanation, though. That's just saying that humans are frail, and this is a failure, therefore it should be expected from humans.