What should TAs do if students disrespect them? TAs are responsible for answering students' questions. But sometimes there are bad-mannered students who don't treat the TA with respect during the interaction. Should TAs just take it and still answer students with patience? Otherwise, they may be complained about by students. Or do TAs have a right to ask students to behave politely before answering them, or to just simply refuse to meet them?
The TAs in question should speak with the director of the course first and foremost - it will be important to have that person "on their side", and they likely have a better idea of what actions are available to the TA.

In a more general sense, my opinion is that you try to treat those students with a sort of detached professionalism, but you are under no obligation to go the extra mile to help them. And you are absolutely within your rights to ask them to behave politely.