In general I agree with you, but having dealt with (less severe) examples of this with some coworkers, it's really, really annoying. When someone simply states their (contrary or contrarian) viewpoint and refuses to admit any evidence presented is valid, you can't win. It's an exercise in futility.
I had a guy simply insisting that evolution wasn't real. "Ok", I say, "what about (found some reports demonstrating observable changes in a species over time)?". "Oh, well sure, microevolution is real, but big things can't change, like humans." And around we go again and again. (Same guy believes that we can't actually analyze someone's genome and that people become resistant to antibiotics, not diseases, and 9/11 was an inside job.)
Show them video, show them photographs, bring in first-person witnesses, and they'll find a way to dismiss all of it. Either because they truly believe what they're saying, or, like a current coworker, they're just a contrarian asshole. That doesn't mean we shield people from these views, but we have to, at some point, accept that not all viewpoints are equal, some simply have no merit and aren't worth discussing beyond acknowledging that some people believe them (would you really want to engage with a flat-earth believer? I mean, it was fun once, but that was enough for me).