As we know, the Titans re-settled Gaia with their human crops, and set about building cities for their free-range human meat. A curious bystander may wonder what, if anything, the Titans get out of the arrangement. While their primary purpose is to shepherd humanity through the aeons, their designers were cognizant of such purpose-driven activity being corrupted over time. Rather than their own computer brains, Titans were architected to run in the background of natural human cognitive processes.
So what the Titans get out of the deal are brains; cheap, farmable, and requiring hardly any skilled labour, humans produce high quality cognitive substrate as a byproduct of their metabolism. The Titans themselves benefit from having a high cognitive capacity, allowing them to exist as conscious entities in nigh-complete control over what is going on on Gaia. It also gives them a highly decentralized cognitive architecture, independent of any centralized control or single point of failure. Which is not to say that the Titans themselves do not depend on any infrastructure; but that they can lose a few buildings here or there, a few thousand humans give or take, and still be able to parse, identify, and solve problems. Their primary problem is, of course, long term survival.
Since the survival of the Titans is yoked to the survival of humanity, and the workings of their minds dependent on human brains, one would think the casual violence of their clashes would be anathema to them. Such a thought, unfortunately, ignores that the Titans are not only cast in the image of brash, violent primates, but are brash, violent primates in a very real sense. Wise enough to reject mutually assured destruction, the Titans nonetheless feel entitled to a good punch-up, and killing a few brain-cells.