This should have been anticipated. It may well have been the man's first flight and the fact that he was an adult doesn't mean he would understand the protocols and expectations of other societal groups. Yes - it was grim but - No - he would probably have not understood the problem.
I recall working in a Harley Street hospital (technical not medical) in the late 1970s. We used to have a lot of Middle Eastern clients in for heart surgery. (The benefits of oil had started to be realised) and many folks made their first ever journey outside their country.
Firstly, they came by air and then stayed in a place called a 'hospital' and saw a white bowl thing on the floor that they had never seen before and had no idea what it was for. After the first few months of accidents, more interpreters were on hand and one of their first duties was to teach Arab men how to use a W.C.
So, I am not defending this man. he may have been drunk and deliberately insulting. Or he may have reverted to beahviour in his village. That is not bad, just different and, if that was the case here, most unfortunate.