What does the ability to remove built in apps have to do with openness? Seriously, this is a piss poor reason to try to attack Android's openness. This is just a design choice on the part of people who ship phones. Be upset that manufacturers put their apps into /system/app and not /data/app, so that they would be removable. (Though most of the time, the space available to the ROM and user installable apps are partitioned and not shared). Open or not, removing data from the read only /system partition requires root. It's not a matter of "openness".

Heck, the comments there do a plenty good job of describing what I've just detailed. Besides, rooting and custom firmwares are not illegal and most of the time will not stand up in court as warranty violations (at least surely not outside of the United States).