Honestly? I think people (in the general sense) are constrained to the amount of complexity they can handle and the world is a complex place so they fall back on picking a choice/hill to die on as a way of reducing the complexity.
Not a new thing, I work with a guy who is an excellent programmer but will argue for ever that OOP is the right way to build software and that he doesn't see the point in functional programming while writing code with map and reduce inside class methods..
The benefit of a dogmatic approach is you never have to question it (otherwise it wouldn't be dogmatic), small government good, efficiency of the market, nuclear bad, nuclear good, emacs better than vim, vim better than emacs, chrome better than firefox, linux better than windows, mac better than PC, religion good, religion bad - pick a side and never think again(TM).
In reality nearly all of life is some variant of "it depends" and there should be no shame in saying "I don't know enough to have an opinion" and if its important then you go look into it.
The fundamental problem is "reasonably informed opinion held until presented evidence one way or the other" is more work than "strong opinions, loosely held".