Perhaps because Microsoft's pre-existing ARM competitors (iOS and Android) all have locked bootloaders as well.

Yeah, I think this is a big part of it. The mobile ecosystem has evolved in such a way that locked-down devices are the standard, and content providers have had a lot to do with that (apparently B&N's decision to lock down the Nook Tablet after having released the super-hackable Nook Color was made almost entirely at Netflix's insistence). I'm certainly a lot more annoyed at MS over their ARM positions than their x86 ones, but this attitude predates their entry into the sector.

Part of it might be the same reason why Amazon, BN, Apple and many Android tablets have the bootloader locked. The Windows RT tablet has ties to content consumption, like 30% or 25% cut of apps and also media sales like movies, tv shows, books, music etc. which are used as revenue(and even shared with OEMs according to rumors). Think about the how consoles are sold at near cost or a loss to make up on the games.

Loading Android or Ubuntu onto Surface or any other Windows RT tablet undermines this, that's why even the Nook, Fire and iPad come with locked bootloaders.

>This is especially disturbing considering that ARM may very well be the major computing platform of the future

Which ARM device has the biggest share of ARM computing devices like tablets? Apple with 80% and rest Android(many with locked bootloaders)?

Why does this come up only about Windows RT tablets that are going to start from zero against the iPad juggernaut? Where are comments like yours in the iPad discussions? What am I missing here? Why is it disturbing when Microsoft is starting to try to do something which Apple has already implemented with wild success?

> Why is it disturbing when Microsoft is starting to try to do something which Apple has already implemented with wild success?

I think Apple (and certain Android manufacturers) have made the wrong choice for long-term consumer welfare as well. Apple's increasing dominance is a tremendous threat to consumers' ability to control their own hardware.

In fact, Microsoft has historically been the good guy on this point. They are a big reason why we have such a large selection of cheap PC hardware. It's disturbing because, if Microsoft decides to move in the direction of locked-down hardware, there will be no major player left to support generic, OS-agnostic hardware. Which in turn leaves Linux users very much high and dry.

So really I sympathize with your perspective. It's ultimately the people who buy Apple products who have subsidized this disastrous trend.