Agreed to a point. But they're far more open source than Apple is. The deepest parts of the code are protected but the vast majority is not. The most important part is that manufacturers don't pay for licensing and anyone can modify the OS through rooting and custom ROMs. In addition, rooting an Android device is far more beneficial for the user than jailbreaking is for the iPhone user.
And, as an aside, (not at you), please stop with the "fragmentation" argument. There's fragmentation everywhere. Look at the latest iOS update on the iPhone 3G. It's a DISASTER!!!! The anti-Android/pro-iPhone users have created the illusion of fragmentation to scare off those who might be interested in the OS. It's not unlike Fox News with it's purported "fair and balanced" crap.