Mostly because freedom is not really accessible for most people, in matter of computing.
You can have freedom to install what you want, the way you want... only a minority ultimately knows how to. The rest is left without a clue in front of their supposed freedom.
When the iPad is presented to people, of course it's no "revolution" to most of us. But for the regular person, it's an easy way to access something which they could have had difficulties to access, before. At this point, choice matters less than the actual possibility to use something, even if this thing is framed and safely guarded, for most.
There are some people who do think freedom and accessibility can coexist; interestingly enough, some of the very people whose work Apple built on (but focusing more on the accessibility part of their work). For example, Alan Kay and Ted Nelson have both long pushed the idea that computer systems can be both hackable and user-friendly / broadly accessible, rather than having to be split into a dichotomy of consumer-appliance versus hackable-nerd-toy.
You can have freedom to install what you want, the way you want... only a minority ultimately knows how to. The rest is left without a clue in front of their supposed freedom.
When the iPad is presented to people, of course it's no "revolution" to most of us. But for the regular person, it's an easy way to access something which they could have had difficulties to access, before. At this point, choice matters less than the actual possibility to use something, even if this thing is framed and safely guarded, for most.