because it is a long running gag in a long running TV show
a gag made a bit funnier by the fact she is voiced by a women who at one point was voted sexiest woman alive.
Hypocritical humor. Kinda playing on the trope of men having high standards they have no right to have, and exaggeration is funny to some people.
ᴳᵒ ᶠᵘᶜᵏ ʸᵒᵘʳˢᵉˡᶠ