The author of the piece, MG Siegler, argues that because carriers can abuse the openness of Android - and in the United States, they do - the net result is that Android isn't open at all. Siegler points to a number of examples where carriers taking advantage of Android's openness actually leads to a more closed environment.
For instance, the EVO 4G on Sprint and the Droid 2 on Verizon have crapware on them, which in some cases can't be removed. Siegler also points to rumours that Verizon may be working on its own application store for its Android devices (they're already doing this for BlackBerry devices). Then there's the curious case where Verizon has made a deal with Skype, so that Skype only works on Verizonified Android phones.
Siegler then argues that these issues make Android less open. The problem with this line of thought, however, is that openness manifests itself in more ways than one. The openness Android users care about is not the fact that they could, potentially, access the source code or whatever - this only goes for a very small geek elite, and since Siegler clearly states he's talking about average consumers, he also knows this.
No, Android users care about another advantage of openness: it leads to choice. You can get multiple Android phones on multiple carriers. You're not locked into AT&T with a single device - you can choose which device and which carrier fancy you the most. Without Android's openness, this would not be possible.
On top of that, it's rather short-sighted to look at the US market alone. Here in The Netherlands you can pretty much mix and match whatever devices you want, and carriers don't fiddle with their phones as much as US carriers do. Had Siegler taken the time to look beyond the borders of the country he lives in, he'd see what openness can lead to.
That doesn't mean that the actions undertaken by US carriers do not suck - because trust me, they do. However, calling Android's openness "a load of crap" because US carriers are crap seems a bit short-sighted to me.