In Sezon burz (the Witcher's Season of Storms), the sorcerer Pinety has this conversation with Geralt.
"Have you ever angled, Witcher? Does hunting attract you?”
“I hunt when I have an urge for a fish. I always carry a line with me.”
Pinety was silent for a long time. “A line,” he finally uttered in a strange tone. “A line, with a lead weight. With many little hooks. On which you skewer worms?”
“Nothing. It was a needless question.”
What is the meaning of his words?
What I took from this was how Pinety thought strange that the Witcher (who had previously avoided gruesome details of what a loose demon was doing to people, and who avoids torture and malice) didn't mind torturing and hurting lesser animals, like fish and worms. How Geralt unconsciously distinguished between creatures that should not suffer, and creatures who could be tortured and hurt at will, even if for feeding purposes.
Please pay attention to spoilers, and use spoiler tags as necessary. I have not finished the book.