"In that raider's cave of a room [...] stood a magnificent man in magnificent armor, the kind of Radiant Mantle of Kingship sonofa[female dog] that doesn't really exist outside of stories and songs; you know, Arthur, Charlemagne, Frederick Barbarossa, Richard Coeur de Lion, all those blood-drunk thugs with good enough press agents to somehow end up heroes to way too many gullible losers. Not unlike me, I guess. But let that go."
-Dominic Shade on Justiciar Purthin Khlaylock, Caine Black Knife
(I, obviously, really like Stover. One of the best parts of Shadows of Mindor was how he had Lando mercilessly mock Fenn Shysa and the Protectors, while playing the Fandalorian stuff straight enough in other parts of the book to make it even out. Nice job with the balancing act, there.)
The Mandalorians are a bunch of blood-drunk thugs who pretend they're not, who abide by a code of honor that is ignored whenever it suits them and adhered to the rest of the time. They're the scrappy underdogs who always lose every war except the one for the history books. To their fans, they're the Everymen who don't have special Force powers but still go toe-to-toe with the Jedi (until they lose), but they add to this working-class hero rhetoric a bizarre fascination with the ostensibly superhuman amount of training that they undergo: the blue-collar elite, I guess. Their conlang was specifically designed to introduce fans of other fantasy IPs, like Star Trek and Lord of the Rings, to Star Wars fandom. (Look, our franchise can change to be just like yours! Buy a copy of Republic Commando while you're here.) They have a ridiculously Mary Sue society of yeoman farmer-warriors with small numbers but who somehow possess tremendous technological prowess - Maori Spartan-Romans with Nazi Wunderwaffen.
And to crown it all, the stories that form the backbone of the Mandalorian canon contain some of the poorest writing in the EU, from a fantasy author that even compared to her contemporaries is one of the more reviled writers in the genre. The whole 'Fandalorian' thing was really bad about eight years ago, but plenty of those obnoxious jerks are still around today. The Old Republic and the Clone Wars TV series sort of gave them a new lease on life.
In the films, Mandalorians spent all their screen time mugging, falling into death pits, running away from Jedi, and getting their heads chopped off like punks. Somehow that bloated into the biggest and most die-hard subset of Star Wars fandom around. Go figure.
ought to have been at least sort of a way to clue you in to that. But you hit enough of the points that most Fandalorians would - indestructibility, "aruetii" shaming, anything and everything Skirata - to make that sort of reaction almost knee-jerk. 
