Totally agree. This also holds true for anyone substantially smaller even other dudes unless they have a knife, gun, bar fight furniture or throw a punch. Unless someone poses a real threat to you, beating up people so much smaller isn't ok.*It's even worse when it's a woman because women's frames even when the same size (height and weight as a smaller male) can't withstand the impact of a man's punch at even remotely the same rate even a tiny man or boy can - that's just reality of how our frames are built. Women can be strong as an ox but bones/frames are a different thing. Men, even ones smaller than the women they beat, can do a lot more damage to a woman.
But you should never beat down someone smaller than you even if it's a small dude unless there's real world justification. Words aren't enough unless they say something like "I have a gun and I'm going to shoot you and you really believe that to be true".
ETA: I haven't seen anyone report she or her friend threw a punch aside from OU boards and the passed down rumor mill. Quite simply, I find it incredibly difficult to believe the story Leb is reporting.