On one level, giants are symbolic embodiments of the unstoppable, inescapable disasters nature sends man's way. Storms, torrential rains, avalanches, these are all nature's giants. But giants also serve as literal stand-ins for human evil, writ large. That latter clan of giants includes Polyphemos the Cyclops, who devoured Odysseus' men. The "Fee Fi Fo Fum" giant Jack encountered at the top of the beanstalk also wanted to eat him. And don't forget the savage race of giants in the Harry Potter series.
The big guys all seem so unpleasant. But are they? Seems to me, they're not necessarily more cruel to us than we are to the creatures that we exploit. If we were conquered by a vastly more advanced race of aliens ("giants") who like to eat exotic meat, we wouldn't really be much more than livestock to them. In fact, there is a movie starring Scarlett Johansson dealing with that very theme ("Under The Skin", based on a novel by the same title by Michael Faber). And there's the savage naked aliens (why is it that movie aliens rarely wear clothing?) eating and drinking humans in "War of the Worlds" (2005). They weren't more civilized than humans, they just had fancier weapons; but even so they treated humans as "just food" (and fertilizer!).
Since giants are creations of ordinary little humans, this tendency to equate giants with evil does not show us in a positive light. It means people believe being powerful and free of the constraints imposed by rules made by others, not having to answer to anyone, would naturally tend to bring out the baser impulses in men's hearts, even unconsciously (some of Spiderman's adversaries, such as Doctor Octopus, Electro and Green Goblin come to mind).
But if there were godlike galaxy-girding aliens with inconceivable powers and glories, forget about caring about us, would they even notice us? Forget "breeding" (ahahaha) with humans, like the UFO conspiracy nuts are always going on about -- why would they even bother? Here's a hint: do we notice the ants that we walk over every day, and wish we could breed with them? Or in a darker, but more immediate vein: if five year-olds were giants, would they trample little adults underfoot when angry? Imagine a hundred-foot tall kid throwing a tantrum in a crowd...
[The Heaven's Gate tragedy happened because its cult members really believed space aliens with superior powers specifically cared about them. Wow. And then there's that certain other religious cult out there that does the converse: it teaches its adherents that, hey, just by joining the cult and paying respect several times a day in a very outwardly visible "I'm devout and you are not, which makes me superior, like a human is superior to a pig" kind of way, they become metaphorical giants among mankind -- not gonna name names though]
But not this giant. He seems to be apologizing for all the harm done by his fellows.
