How can Winston from 1984 be compared to a rock?

Apparently Winston is a drunkard in 1984. He can be compared to a rock because there's nothing new under the sun for him. He eats, drinks, and is merry. Nothing else happens and it's the same routine. A rock is obviously non-living, but a rock doesn't have much of a social life, similar to Winston. They both relate because they are both, well, monotone.