Again I don't think its confirmed by anything canon one way or another

Again. We have the statements of the man himself, his followers and his formers followers, and the themes of the narrative presented this far on one side and... "Nothing says it isn't true" on the other.

If Edward Sallow doesn't believe and Graham knows then the entire legion is just a prank and Grahame critiques aren't sober considerations bought on in the wake of his experiences Spoken as he attempts to atone through flawed means but him talking about that time he pulled an epic prank. Graham isn't a man who after his very lowest point reconsidered everything he was to return to the faith of his youth tainted by the horrors he perpetrated, but a dick who did a prank and is doing another one.

The people speaking of the ways tbe horrors of the legion have impacted them as if they were a favor aren't sober and horrifying critiques of cultural imperialism and a reframing of "They plunder, they slaughter, and they steal: this they falsely name Empire, and where they make a wasteland, they call it peace." In the context of fallout but just an unfunny joke.

It renders the point of legion characters nothing, it isn't supported textually and it doesnt add anything. It just seems like you dont like the legion and therefore they must be illegitimate. Which Imo is a less scathing critique than if they are legitimate.

But imo his past as a member of a far-left mutual aid org and very deliberate choice to use the Roman Empire as inspiration for a culture which could be a far stronger military force, and far crueller culture than the former Arizona tribals were, leading directly to his own personal enrichment points more to a self-aware and cynical interpretation of his motavations

This renders his appeals to actual legitimate (or at least legitimate as far as the writers were concerned) philosophy entirely meaningless. The scene where you meet the leaders of the raiding faction behind the most horrifying things you have seen and he starts quoting hegel and genuinely arguing his case becomes a farce and meaningless. If he didn't belive, why would he need to justify it to an outsider?

He's mussolini, he's all the national syndicalist who historically decided to adopt far right ideologies rooted in their former leftist frameworks. Or... he's just doing a prank.