Not sure if there is a specific, objective answer to this question but I get the same everything I want to buy a piece of hardware and try to check if it's Ubuntu / Linux compatible:
Required OS → Microsoft Windows 7 (32/64 bits), Microsoft Windows Vista (32/64 bits), Microsoft Windows XP (only 32 bits), Mac OS X 10.6.2 or higher, 10.5.6 or higher, 10.4.11 or higher
Thing is, the product usually does work flawlessly with Ubuntu. Why don't these people even mention that in the product specifications? Why do they always make it harder for the (admittedly small) Linux-using part of the population who want to buy their products?
It's not like including that information somewhere would cost them money, would it?
as far as I understand, they don't add ubuntu / linux to the list mean that they don't officially support it.
By officially supporting ubuntu / linux mean that they will have to answer every support question. This off course will add cost to their operation, given the range of ubuntu / linux configurations.
Vendors probably feel that they can safely ignore Linux / Ubuntu due to low perceived market share. Presumably they think that the tiny amount of money spent to add "Linux 2.6.32 and above" to the package is not justified by the small number of revenue generated by the few folk who will buy the item based on that support.
Or maybe it's not that. Vendors generally develop their own drivers for Windows, and those drivers are often closed-source. The vendor retains complete control over the functionality of the device, and does not have to worry about some geek tweaking the code, modprobing the new driver, and complaining to customer service if the device doesn't work properly.
Frankly, even when the package does claim linux support, don't believe it. I've been burnt in this way by ASUS, whose idea of "Linux support" is providing a CD with an ancient, non-compiling version of someone else's (RaLink) chipset driver and telling the user, "Go compile it." When I contacted technical support, I was told that they only support kernels up to 2.6.22! I'd like to believe that RaLink is unique in this, but I don't.
Does anyone know if the vendors that actually work with Linux developers to support their devices under Linux (HP and IBM come to mind. Intel?) advertise "Linux support" on the hardware they sell? I haven't thought to check...