You just have to look at human behavior in more worldly way to understand the rationale or lack of common sense in terms of how people argue in a video game.
First thing to remember is this is the internet and it’s easy to get mad at someone and insult them when they are unknown or a pixel; one of the cons of how easy it is to communicate now is that it’s also easy to be casual about it all and indifferent to how one might make someone feel.
Next up when someone gets triggered and is losing, they will often resort to insults, and trying to bully people since they are man-baby-hurt. Once triggered say goodbye to a lot of things , notably common sense, reasoning, etc.
This is why you end up with these nonsensical arguments that generally start with BG damage; with zero context. You might have been flag sitting and fought off 3 rogues but since you have low damage compared to the mouth-breathers in the middle you are bad. Not saying high damage isn’t a factor because it is but it’s a primary means of insulting someone when you don’t have anything else.
Other things that come into focus for someone triggered depending on how they are or what they do is arena rating; I quite often get told how bad I am at Arena despite having 0 rated games in years. (Not my preference)
I have even had some folks insult my server. I mean gee whiz, does someone actually think or believe, that in today’s retail with cross realms and a very small “community” that is truly going to be an insult. It’s hilarious
So it’s not surprising that someone would bring an IO rating or whatever into your PVP debates since they are upset; they are “clawing/trying to get air” and find something to grasp onto in order to make an attempt to “win” or at least feel better about themselves.
Does it make sense? Not from a logical standpoint but from an emotionally triggered ego/personality you can’t really predict the lengths and “exits from reality” that someone will actually go…
My advice is just have some fun and troll them; I had one guy who insulted me about being survival and trash and how I would never get invited to his groups so I linked him his last dungeon which was a non-timed Underot 9 and then my last dungeon which was a +2 (Sure, this was a fortunate coincidence, but it was priceless, regardless )
Anyway have a good day and sorry for the novel