what does paul d mean by calling sethes love too thick

Sethe enjoyed only twenty-eight days of freedom before she was tracked down by her old master. Rather than allow her children to be returned to slavery, she attempted to kill all of them, succeeding only in killing the baby girl. Paul D regards this as the most heroic of love. She loved her child so much that she refused to let her go back to slavery. Her only option was infanticide. Paul D suggests this as excessive love for her child which he calls "too thick".