That's just the difference between an average male and female physique. Ask any female who fought or arm wrestle with their boyfriends or brothers, they would know. Even stuff like opening a jar or carrying heavy groceries. Research have shown that male have better upper body strength than female.
So true, those women that tend to think they can best a guy usually have never fought a guy. So far all of the vids clips I've seen it's overweight women making the claim which scews the sample survey in my head over I think most women just don't realize just how much stronger guys get during puberty and later, especially if they are athletic boys, it can be quite a lot. In Rae and Sykkuno's case, Rae and Sykkuno both go to the same gym, she has seen his physique and knows he's pretty buff, she's admitted this on stream. Rae herself looks like she's a hundred pounds soaking wet and Sykkuno he's probably 175 - 180 pounds. He's also taller than her by quite a margin. So yes she's going to lose... badly. Sykkono is going to win.