It is reasonable when you call him wearing the armband an insult. Nowhere near it. One of the most important traits of a captain is being influential both on and off the pitch, something that Barella has and none of Nagatomo, Guarin and Gags did. Barella's mood swings makes a bad fit for a captain but let's not make it like it's an insult to Inter values to have him wear armband for few minutes.
Nagatomo and Guarin were during the times while our team was stacked with garbage players and we had no better. Nagatomo was well matured and a true professional. Was he a great player? No, but like I said, we had no choices back then.
It's complete different situation now. We have quality players now. Barella might be a quality player but he is way too immature. Besides of that, he tends to disappear when it matters the most, especially as a "best midfielder of the league" attribution. You can't just bring shitty excuses like Nagatomo, Guardin and Gags for something that doesn't just fit.
Barella is no captain material, and seeing him with armband ahead of some others which are clearly better options, then it's irritating. I don't get where do you guys get the idea of quality player needs to be a captain automatically, no matter if he acts like a teenager all the fucking time.