There's plenty of journalistic value in interviewing him and the audience will be very interested in hearing it.
I'm not sure what being outraged over his interview is going to achieve Signalling you disagree with what he did? To protect people from his hearing his dangerous words? To punish him?
IMO hearing his rationale, seeing how he convinced people, the lies he tells himself, etc should all be analyzed and publicly scrutinized. It's not like he's promoting some new venture or something.
Associated with what? An interview being done with a public figure?
They aren't suddenly friends with the guy because he gave a virtual interview over Zoom at the same event as them.
You don't need to be constantly publicly showing your outrage to make it clear "x person bad". We get it. We know he's bad. Even without such brave moral heroics.