I am often amazed by, while I also participate in, the intractable positions about certain firearms.
Quite often there is no rational reason to take the position, nor a rational basis to defend it.
For a lot of things it comes down to an emotional decision. We simply like something and liking it we want others to like it too. Hey! Human nature again.
I have my gun prejudices, I try really hard not to mock others for theirs. If there's some factual basis for showing superiority, I try to keep it there. Oftentimes while touting the superior feature of our chosen baby, we forget the superiorities of the other.
We also fixate on our advantages while forgetting that the gun/round we are mocking may have been intended for a purpose completely contrary to the one our favorite was.
There are also a good many of these debates where the guns or rounds being compared were designed for the same thing, and do it completely differently.
The classics are, of course:
M16 vs AK
Stoner gas system (incorrectly called direct impingement) vs piston.
1911 vs Glock
.45 vs 9mm
Auto vs revolver
Semi vs Pump
Buck vs Slug
Irons vs Red-Dot
I am sure there are many others.