The "full-grown" is why
She's a fleshy refrigerator of advanced age. By now, the excess weight has likely worn out her joints and she's likely developed osteoarthritis in those knees
PLUS she's got a rooting interest in Detroit
Therefore, she's a miserable old woman and, as you know, misery LOVES company.
In conclusion, if her gesture of disapproval produces even a microgram of sadness in any of our boys hearts, especially true if accomplished during moment of a jubilant gathering, she will feel pleasure
In simpler terms she's a troll, in need of a feed 😁