Not exactly. It's more like saying Windows PCs are more prone to hardware problems than Macs. With the iPhone and Blackberries, you have devices from one manufacturer with a relatively high standard of quality control. Windows Phone isn't so rigid, but still, the companies currently manufacturing Windows Phone devices are on the relatively high-end.
With Android, pretty much any schmuck can sell a cheap tablet with a resistive touch screen running the OS - you only need Google's approval to ship with the market and their proprietary apps preinstalled. I didn't catch in the article whether this study only included Android handset manufacturers like Motorola and Samsung, or if it also included manufacturers like, say, Augen. It would make more sense to compare Google-approved devices to Windows Phone 7 handsets, or HTC phones to the iPhone, for example.