I'm curious, she states that she has argued with him in the past and that it would've revealed the kind of person he is.
What have they argued about in the past? I would almost say that having argued with someone multiple times that you don't even live with is a red flag for happening at all, instead of a green flag that he's not a bad person. I'm curious if the context of their argument would make more or less sense.
I don't mean random opinionated internet comment arguments. If I think about online acquaintances that I actually message privately, like Discord, then I don't argue with any of those people ever. The people I actually privately want to know and have added as friends, anybody who id even come close to calling, for instance, "brother", I don't argue with any of those people.
Random dude on a message board who has awful takes, of course, but I don't add that guy and send him money or consider letting him move into my house.
I mean sure, if you talk about common interests with people youre less likely to argue, but if you build actual relationships and communicate a lot, arguments are bound to happen. Not arguing with people you are actually close with seems unnatural, whether on the internet or in person.
I think it depends. I'm very logical and my brain likes to identify issues and cleanly solve them. Arguing in circles is a waste of time and energy. Basically, it's complicated. I think the nature and frequency of the arguments are important to get a better idea of OP's situation, that's why I asked.