Probably just someone who is really animated about the topic, and hasn't grappled with the underlying biology very much. There's a lot to take in and understand about how the immune system works, I don't fault people for misunderstanding it or even having strong distrust for pharma. I try to respond with that in mind, and assume people aren't being malevolent. Even if they are, it's useful to publicly shoot down bad ideas and bullshit.