If this user has a reasonable answer for what looks like a glaring inconsistency in their claims; I was intending on politely bowing out.

This guy argues in a similar style as vegans and just extremists in general: avoiding simple refutations, identity shenanigans like claiming not to be vegan (sometimes with multi-accounts), and writing in as gaudy a manner as possible to emphasize intellectual superiority. There's also the biggest indicator, which is being willing to write walls of text but becoming coincidentally silent or evasive when you ask evidence based questions, such as a simple clarifying question regarding the methodology of the studies they cite.

Or even the simple question of whether they specifically researched the topic they're arguing about.

Edit: All that amateur writing analysis gets blown away by evidence, however. Psychopaths like that are rare anyway.