Platypus truther - noun - Someone who doggedly, ruthlessly, and almost to the exclusion of anything else (including good sense) espouses, defends, and picks fights over a position, idea, or hypothesis that is completely and totally around the bend. Even taking into account the context of this person's other activities (social media history, books written, and so forth) it makes absolutely no sense why they would claim to believe such a thing, let alone fight with people over it. There is absolutely no way of telling if they're communicating in good faith or not. It could be trolling, it might be absurdist peformance art, it could even be software mediated madness, or some other combination of phenomena.
The term was coined as a description of a Twitter user who is adamant that platypodes do not actually exist. The individual's claim is that all drawn depictions of the creature are fanciful, all video recordings are special effects, and all live specimens are actually mutilated creatures of other types. Nobody knows what the hell they're on about, so all we can do is shake our collective head and close the tab.