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.
Tell the typical buyer of the SL1 that they can "micro-adjust the autofocus" and they will say, "I don't need that." Tell the typical buyer of the 5DIII about all of the creative filters and scene modes they're missing on the 5DIII, and they will also say, "I don't need that."
AFMA would be no more of a selling feature on the SL1 than creative filters and scene modes would be on the 5DIII. Some people here would scream in protest if creative filters and scene modes showed up in their 5DIII. That would be a case of more features making a product less attractive.
When Leica introduced a "snapshot" mode on their $6K rangefinder, that feature was greeted with ridicule and scorn by their user base. It was something they would never use.
The lesson for the manufacturer is that you don't include features just because you can
, or just because they're cheap
. That approach is as likely to turn away some buyers as it is to attract others. Instead, you choose a package of features that make sense for the intended user and how they're likely to use the product. Camera makers don't just compete to offer more features, they also compete to offer more intelligent, more coherent design.