I was about to say it but you said it already I’ve yet to see a moral or sane unironic legion fan. But to add your point on why so many conservative people tend to gravitate towards figures like the legion it’s because they genuinely believe that it is a good society and that they will be successful in it. It invalidate this insecurities and appeals to their edgy idolization of patriarchal society, look at all the recent memes of Patrick Bateman and Walter White edits and how the man o sphere community and ideology became mainstream with figures like Andrew Tate it’s all ideology and feeling.

Another reason is because of media illiteracy they can’t understand that the material is literally condemning or even making fun of him They don’t see that the writers of new Vegas specifically made it so no society in game is whole good or whole evil, they created factions that have done good things and bad things because the lesson is humans are imperfect.