I never got to see the raws. Did Endeavor say something about Americans or did he just call All Might a meathead (or equivalent)?
Reading the WSJ translation, I don't get why Bakugou would make that kind of face, he got angry when All Might implied that he was scared, but when All Might puts his hand on him he wasn't saying anything that might be implied as an insult, so.. something more inocent? as in "my hero is touching me!!"
He might just not like being touched. He doesn't exactly go out of his way to initiate physical contact unless he's fighting.