at the people who think this is because of piracy. The PS3 has been hacked (even if it is a damn hard way to do it and that only a few thousands in the world are able to reproduce) but that doesn't mean we will have custom firmware available for everyone in a year. I am betting the PS3 won't be massively hacked before its death (if ever). Blank blu-ray discs and burners are still too expensive to ever consider making copies. It is just not viable.
Also, I doubt there are many outside using this feature either. Maybe just a couple of millions. Sure, you can create programs but unless you are creating something tailored for the PS3 (like a media center or similar) it is just a hobby.
However, as mentioned before, it is the fact that features are being removed compulsively from models that had them originally. You can't keep it if you want to connect to PSN, which isn't as "vital" as Xbox Live for the Xbox 360, but it is still much more important than the Nintendo Wi-Fi. For example, what if they decide to kill PS2 backwards compatibility in the original 60gb unit? Emulation is done via hardware, but there is nothing suggesting they cannot just do that with a firmware update.
A console is a closed platform, so we can't really decide for ourselves what it is supposed to do (we can modify it to do what we want to do later, but originally it is the company that decides what it should do). However, taking away existing features is nonsense. They could decide to block all the blu-rays of certain studios working in all their own blu-ray players. They could make all Bravia TVs to stop playing, say, a determined video format.
You bought a VW car. Now imagine tomorrow several mechanics arrive to replace your 5 speed stick with an automatic gear because it is more secure.