Well, it all comes down to: it's their school, they can set their priorities any way they wish. I could argue against their method as strongly as they could argue for their method, but at the end of the day, it's their decision.
I grew up in Chicago during the 60s and 70s. The old junior colleges (Wright, City Colleges of Chicago, etc used to be horrible, just horrible. Even back then, many classes taken there wouldn't transfer to 4-year schools. I imagine that many of the people sitting on the adcom are of the same "certain age" that I am (or at least darn close to it) and may have very strong feelings about the 2-year colleges in Chicago and the surrounding area. Not having lived there for about 30 years now I couldn't possibly make a statement for the current efficacy of the Chicago area 2-year schools.
However, here in Virginia, the community college system is alive, well, and thriving. There are, of course, 'bonehead' classes that will not transfer to 4-year schools (and never have), but our community colleges run several very strong programs which are designed for direct transfer and even for guaranteed admission into our statewide institutions including UVa, Va Tech, William & Mary, JMU and VCU, none of which are easy to get into by any means.
Anyhow, thanks for your patience describing the UIC admissions policies (official and unofficial). It's been an education. ;-)