The felines had no word for hot or cold, they simply referred to those as not-warm, a convention widely used through out their language. Comfort was the norm, and thus anything that fell beyond those boundaries was simply not-comfort. They had no word for wet, or tired, or hungry, and no understanding of why such a thing would even need a name.
This confused the translation for a bit, since the humans were rather keen on measuring the exact amount of comfort, or discomfort in any situation. But they were not-cats after all, and their illogical behavior was to be expected.