It is not unusual for this kind of things to happen in the Eastern parts of the world. I had a friend who has to do little errands now and then for professor as interns. It is acceptable practice if professor does not go overboard. On the other hand, most student enjoy doing that as they are scoring favors. However, there are instances that students are compelled to do more with fear of possible bad marks on the records or other retaliations.
In the US, professor like any authority figures weld great power and need to be careful of what they ask and how things are construed. Something seems innocent may be interpreted differently if asked by position of power. With so much to lose as international students, how could anyone dare to decline any types of requests.
It is easy to say "you should have say something" but for international student who do not know our rules, laws or customs may not in position to make such objections.
I can understand the lack of collaboration on the story. Some hoping not to burn any bridges, others wanted to forget of the whole ordeal since they have graduated.
One question to ask here is if the professor ask students with other background doing the same tasks? If the professor only target specific group of students, there could be malice with the intend.
I read a lot of cases where international workers, maid and students were preyed up on. of. I like to see a on going in-depth investigations. This definitely have labor law as well as ICE implications.
