The probability of truth is reinforced by the hierarchies of loyalties / animosities in the armed services.
My section; my platoon; my company; my battalion; etc etc up to my service, e.g. army v navy or air force, against the others.
I know from my own recruit training that company versus company conflict nearly blew up into a full on brawl with every weapon available to us after being stood down for the night, which meant every weapon but no ammunition. As with the SS / Heer anecdote I mentioned, vigorous action by superiors - mostly sergeants and warrant officers (not sure if warrant officer is same in US - here I’m referring to the most senior NCOs who control all NCOs in company and above units / formations e.g. a battalion regimental sergeant major is a fearsome creature who sits at the right hand of the battalion lieutenant colonel and potentially outranks in practice all battalion lieutenants and the occasional captain) averted a significant casualty list.
In WWII and subsequent conflicts it was common in Western, and probably other, armies for conventional infantry units and commanders, especially senior commanders, to look down on special forces type units as some sort of show ponies who got undeserved resources and political / public admiration.
It’s not difficult to see how the same mentality in Germany in WWII could have produced hostility in Heer units towards Waffen SS units, which could have been compounded by the rampant propaganda extolling the supposed superman abilities of the SS.
I’m inclined to suspect that the fascination in some quarters nowadays with the SS flows more from its own propaganda in WWII and nifty uniforms rather than an objective assessment of the SS as soldiers (the SS “soldiers” being those who did a bit more than guard concentration camps etc under the command of their glorious leader, the weedy and bespectacled failed chicken farmer who, oddly enough, never figures as the stereotypical SS “soldier”).