Was that normal for the cultural circle?
Yes, completely normal.
Probably yes, and now?
Point out that it is not normal in
our cultural circle and at least should be refrained from on carpets. What else?
He is a guest in a country and may feel at home
Uh... no? Only up to the point where certain etiquette rules, which make us feel at home here, are not violated. Spitting on carpets crosses a line for me.
Fun fact: During my PhD, I had a Chinese office colleague for two years. At the beginning, I had to point out to him that loud farting in the office is considered rude here – he was completely surprised. And then he would go elsewhere to fart.
He was a nice guy. You just have to say something if you want something. The attitude toward bodily noises in China is obviously completely different than here. Slurping, burping, farting – all done publicly and in company.
Until the end, he took power naps snoring in the office when he was tired. Whether I had students there or not was of zero interest or disturbance to him.