Well, you are welcome to defend it as a business decision. However, Canon's policy of going out of their way to cripple their lower end products does make them less attractive (and difficult to recommend to someone on a tight budget!)
This is where we disagree. The SL1 is no more "crippled" by the lack of AFMA than the 5DIII is "crippled" by the lack of creative filters and scene modes.
Canon has a nice 2,500 word article on their web site on AFMA and how to do it. That's about 5 typewritten pages, single-spaced. Who has time for that? Advanced users and pros ... and no one else.
Which other features would you suggest removing based on this doctrine ? Support for raw seems like a pretty good candidate -- how many pages does it take to discuss the finer points of that ? Also, what do you think of having a white balance adjustment on two axes (not even a color temperature slider -- a two axis amber/blue and green/magenta control instead). The Rebel also has in-camera correction for CA and vignetting, so it's not too much of a stretch to think that maybe AFMA belongs there.
So I'm afraid in conclusion I simply don't really buy your theory that Canon chose to remove AFMA to make a more minimal, focused and tightly integrated, easy to understand feature set. (the two axis white balance is the nail in the coffin for that theory -- there is no way the average rebel user understands what that feature does, let alone how to use it effectively)
I have already discussed at length why creative filters on the 5D are not analogous to AFMA on a Rebel body (basically the creative filters need to take up real estate near the top of the decision tree to be useful. 5D users would laugh at them but not really be too upset if they were, like AFMA, buried in a 3-level menu so that they didn't interfere with typical operation)
Let me ask you why they chose to omit the cool creative filters and scene modes in the 5DIII? (Hey, I would really like them. ) Or why they chose to include the green Auto mode on the mode dial of the 5DIII?
It's not just a question of whether something can be added without too much trouble, but whether it belongs on that camera in the first place. Snapshot mode on the Leica rangefinder obviously did not belong. Likewise, it is arguable that two axis white balance adjustment and other features don't belong on a Rebel. Some things we can guess at, but we'll never know. But not knowing doesn't stop gear forum people from complaining about all of the injustices foisted on us by nefarious marketing people infected with this wrong-headed desire to make a profit.
Another analogy: Wordpress.com offers three price levels for blogs they host, from $0/year to $99/year $300/year. To get the ability to edit CSS on your blog (a "premium" feature), you have to go up from $0/year to $99/year. Of course, you get some other premium features bundled together for that price. And yet how much does it cost them to enable the "edit CSS" feature? This feature lets you make little tweaks, like adjusting the default width of images on your blog. It should be "standard", right? They could easily offer the "edit CSS" feature somewhere where it wouldn't bother anyone who didn't want to use it, and yet they don't. Should we cry about how the basic $0/year blog is needlessly "crippled"? Are they showing "contempt" for their customers, as some people on this forum would argue, or are they just making rational business decisions?