It's interesting that you brought up the car, so let's use that example. Would you argue that you should have the ability to remove emissions-regulating devices from your car? After all, they add weight, complexity, and reduce power.

We have emissions regulations. We also have the DMCA which prevents anti-circumvention of piracy protection measures (which the modifications in question aim to do). We, as a society, have generally agreed that emissions regulation is important. We have also agreed that software piracy undermines the viability of the computer/electronics industry.

It's not as black-and-white as "it's mine and I should be able to do anything I damn well please." These modifications have an effect on society at large. In the case of the car, your "right" to modify your car does not trump the rights of society to not have to deal with whatever modifications you deem you deserve. Similarly, even game console modifications have externalities and effects on the industry. They damage the online gaming ecosystem. They reduce revenue. The prevent game consoles from patching and regulating online play.