re: Why is low brow humor so loved and accepted in the MCU, but reviled with The Last Jedi

Because MCU and Star Wars are different. MCU is mainly targeted at children and man children, so it's accepted. Star Wars has a fan base of children and adults, while some humor is appropriate (like Han Solo provided in the original trilogy), the crap we got in TLJ wasn't (Luke's weird green milk, Rose as a character, etc).