One of the things I object to the most with the Mallard Fillmore comic strip is the grotesque nature of the caricatures of people that the artist targets for ridicule and abuse.
A prime target is Hillary Clinton.
Everything about the caricature is meant to portray contempt, from the crossed eyes to the buck-teeth. The crossed eyes in particular seem to be an attempt to convey lack of intelligence or stupidity.
You can see it to even greater effect in this highly offensive caricature of Barbara Streisand:
Here, the crossed-eyes are paired with a witch-like nose and cheek bones that poke out like sharp angles.
Tinsley seems intent on portraying these women in the most unflattering and ugly way that he can.