I disagree with you completely. Presentations are a public dialogue about topics; that's literally their purpose. By presenting on a topic, you are putting your

I disagree with you completely. Presentations are a public dialogue about topics; that's literally their purpose. By presenting on a topic, you are putting your ideas and viewpoints into the public sphere for discussion, sharing, critique, criticism and further development. Hiding one side of that conversation makes no sense whatsoever. You can disagree respectfully with someone in public. That's pretty fundamental to progressing the dialogue. Hiding it means people don't then get to evaluate opposing viewpoints and understand the relative merits of each. My colleagues and I disagree about our work - in public, in front of each other - all the time. The trick is to do it politely and respectfully, which is overwhelmingly the case. This is how we all learn from each other and develop a higher overall standard of output. And all that considered, in this particular case why not just ask the original presenter how they feel about it? Surely that is the authoritive answer to whether there's even an issue here.