That's not what it's about for them. All they care about is avoiding the feeling of losing by whatever petty means necessary.

If you've ever had the misfortune of watching a ragequitter stream or being in comms with one, you'll quickly realize that every time they ragequit you'll always, always hear a justification for it. "They're playing a bullshit character", "they're using a cheap tactic", "I lagged", "[thing I meant to do but clearly messed up] didn't work for some reason", etc. The pattern here is that losing is never their fault, and they genuinely believe that, or at least they genuinely WANT to believe that.

And nothing else matters. Who cares if your opponent still gets credit for the win? Who cares if you don't get your match rewards? The only thing that's important to a ragequitter is that they didn't have to see the "DEFEAT" screen, and that allows them to continue feeling good about themselves because they can pretend that they "didn't really lose".