I love the show! I think they yell so much to represent how dysfunctional the family is at times. My own family is dysfunctional like that, my mom and her 4 siblings have the same sort of dynamic, they all talk over each other, sometimes they yell, they disagree and argue but there's a strong bond that transcends all that. The show means a lot to me because I think it helps normalize what it's like to raise a kid with Asperger's--my son has Asperger's and I feel like the character of Max is pretty accurate.
Speaking personally, I'm not a yeller--I think if you start yelling at your kids you've lost the argument because you lost your temper and my kids find my steady, even "meltdown voice" more annoying than if I was yelling at them. And it really bothers me that Max's parents seem so dense when it comes to ABA. They pay all that money to his very knowledgable TSS, whose methods work wonders with their son, and then they argue with her about her methods and ignore all her advice! Then they have the nerve to act all high and mighty like they know best because they are his parents--why the heck did they hire her then?! ABA principles work miracles, I see it every day in my job, Gabby is a rock star and the unsung hero of the series!