Because she took the seat telling the mother that she would move, intending that the mother would be too embarrassed to make a stink and throw out an old lady.
And she was right, the mother didn’t have the guts to throw her out.
She didn’t even make any pretense of right.
She just used force to accomplish her goals, using her weakness to make sure that the other party wouldn’t use force in return.
You just try pulling that on me.
I would have picked her up and thrown her down a staircase.