A friend of mine who is from Japan told me that his professor in USA puts the feet up while talking to him. He was saying that he felt very bad with that. Is this acceptable culture in USA academia?
I've done my PhD in Japan, and have had much contact with professors in America and Japan.
The academic relationship and work culture in both countries are very different. In America it is generally not regarded as bad when someone puts their feet on the table while talking to you.
I had bosses and advisors in the US who did this. However, in Japan, the advisor-student relationship is more respectful and professional.
I would like to tell you that you should ask the professor to refrain from putting their feet on the table, but if they do it in their office, it is pretty much up to them. Since the office is the professor's space, I do not think it is your friend's business to ask them not to do it.
In the orient showing somebody your feet/shoes is a sign of disrespect.
A person who puts his feet on the desk in the western world shows that he (this is mostly done by males) is at ease/relaxed in an informal atmosphere. However, also in the west this behavior is normally only shown by people who are talking to their subordinates or peers at their own hierarchical level.
Perhaps your friend could tell the Professor, in a somewhat apologetic tone if he doesn't feel confident enough about their relationship, that in his cultrual background, putting your feet on the table is an offensive act, and while s/he is certain the Professor does not mean it, s/he (the PhD candidate) is very distracted by it, so s/he is asking for the Professor's consideration on this matter.
That is, the request to not do this can be made with deference rather than as a form of rebuke.