Maybe so, but that doesn't mean they should not pre-install a free OS. The fact that they official support Ubuntu gives confidence that it will work with (almost) any linux distro (possibly with some work on your end).

And those bits on the HDD sure make it harder to install a different OS over the top of it.

I don't understand how you can be snarky about a company that picked an OS (I, for one, am shocked that they picked a popular distribution) and then got a good set of drivers and tools for it, packaged it up and want to support it.

If you want to install something else, install something else. If you don't want to pay the Dell or the Sputnik tax, then go buy something else. I don't get the shitting on Dell for trying to accommodate another market segment.