An Iranian immigrant can't help but advocate for their political views simply by existing. Living and working in the US is an assertion that they should have the legal right to do so. Simply by being glad to have them as a coworker (the most anodyne possible affirmation that everyone generally expects from the people around them) you are making a political statement. If I say, "I'm glad you were able to make it home," I'm expressing support for the court case that invalidated the executive order that allowed them to come home.
As long as some parts of politics are working to harm the people you work with, coexisting with them and exchanging pleasantries is political.