It does make sense when you think about it. Civ AI is basically a giant set of if... Then... Statements, from what I've read on here. By that I mean it has a set of rules and follows them, making it predictable and therefore also there being an optimal strategy to defeat it. Play Civ enough and eventually you'll find that optimal strategy (or one of several). The people who post here are more likely to be the type to play Civ a lot, and therefore 1) more likely to be skilled than your average Civ player/owner. 2) more likely to have found an optimal strategy than your average Civ player/owner. They're probably right in that they find Deity easy, but that's probably just because they've played more than your average Joe and probably have found an optimal strategy, even if they don't realise it. If you want some evidence, notice how many have a build order or have a set way of playing. I'm still new to the game (my copy is out of action until they fix a bug) and I have a far less pre determined order to how I do things because I haven't found an optimal strategy.