ARAM Behavior

Why do people take ARAM so seriously? I've seen so many players approach it like a Ranked game, with so much attitude towards other players who might be feeding or playing the champion wrong or whatever. The main aspect of ARAM is getting a RANDOM CHAMPION, more than likely someone you rarely or never play. So why do players get all butthurt if I'm a support main but end up with Kalista, who has severely different mechanics than my supports? I play ARAM for fun, I know it's a really difficult concept in League. I play it in between Ranked games or if I don't have time to commit to a full game. ARAM is for shits and giggles, not realistic high-level play.