Same when I saw it last weekend. The kid (maybe 4 or 5) wasn’t crying, but literally would NOT SHUT UP through the entire 3 hours. Makes those quiet, impactful moments a bit less so when you have a kid yelling “MOM, IS THAT THOR? LOOK AT BADGUY GO BOOM!” at the top of his lungs. Mom never even gave the kid so much as a “shhh” the entire time. I was fuming.
I’ve got kids, and I know how wound up they can get. But for hell’s sake, take them out if they’re a distraction to literally everyone else in the theater.
Disclaimer: I’m much more tolerant when it’s a “kids” movie. I would have little issue with kids jabbering through Toy Story, for example.