User blog comment:The Milkman/End of the Line/@comment-2250460-20120703061551/@comment-4950455-20120703222556

There's also probably some confirmation bias in there - every time it sees synthetics and organics come into conflict (regardless of the ultimate outcome), it just takes that as more proof of its "cycle".

My gut feeling, based on what it says about its creators, is that the Catalyst was created to find a solution to organic/synthetic conflict (quite likely a conflict, not an eons-spanning cycle - the relay builders probably weren't around long enough to tell). Somewhere along the line it decided that the conflict was insoluble and began focusing on compensating for this inevitable law of the universe, by preserving advanced civilizations in Reaper form. It stopped being open to the possibility that organics and synthetics might come into conflict, or that said conflict could end without genocide, a very very long time ago.