Recap: Cronus is the youngest of the Titans, born to Uranus and Gaia. He is also the smartest, and the most ambitious. Not bad. Cronus is the first to respond when Gaia demands that Uranus be punished. He's also the one who does the actual… castrating. Yeah. In return for his loyalty he becomes the ruler of the Titans, but sadly, he learns just after taking the throne that he is doomed to be replaced by one of his children. Determined to escape his fate, he decides to eat his children as they are born. Well, then.
Despite the fact that Cronus is not the primary protagonist of this story, he may actually be the most interesting character that we get our hands on. Cronus is the closest thing that we've got to what classical literature would call a tragic hero. Throughout the course of the story, he gets to be both the good guy and the bad guy, and his eventual downfall is the result of fate rather than personal action. Basically, he gets shafted.
Think about it: Cronus rises to power by doing exactly what this mother asks of him, and instead of being properly rewarded, he's told that one of his own children will eventually overthrow him. How would you feel if you finished all of your chores and, instead of getting an allowance, your mom told you that your son would one day kick you out of the house? Seems like a bogus deal. Of course, Cronus' response to the prophecy is to start eating his kids. That part doesn't really play in his favor.
The upshot of Cronus' transformation from hero to villain is that we, as readers, have the choice either to hate or pity Cronus. Or both. The same thing can't be said of characters like Gaia and Uranus, who scholars would call "flat" because we only see one side of them during the story. Even Zeus, who is the protagonist of the story, seems a little one-sided next to Cronus.
One last thing: in certain versions of mythology, Cronus is eventually released from Tartaros and given rule over the Elysian Fields, where the spirits Greek heroes reside after they die. So this makes us think that certain authors did pity him. (We're with them.)