I completely understand the frustration people may feel over an unusual and relatively high fee. However, a little perspective makes it pretty clear why it is there and how it came about. I have no inside knowledge of this, mind you. This is just my personal (slightly cynical) observation.
Cal Poly’s reputation occupies a unique middle ground between its CSU economic status and its UC-like academic qualifications. That makes it a tempting target (rightfully so) for out of state students who want the benefits of an excellent education at a lower price. It is one of the factors that makes Cal Poly so attractive to in-state applicants, as well. Trust me, it is one of the top three responses that I get when I first tell people that my children are or will attend. #1 is “It is so beautiful there.” #2 is "What a great school, they are so lucky to have gotten in. "#3 is “A UC education at a CSU price.”
The fee then works in two ways, which I am not necessarily defending, just pointing out. #1, it tests the basic capitalistic principle of setting prices that the market will bear. If Cal Poly is closer to a UC in educational reputation, then let’s set the price closer to a UC (Cal Poly is also more expensive for in-staters as well, so OOS actually pay both of those increases). #2, the fee goes to a fund that helps off-set tuition costs for lower income in-state students. This helps to mollify the loud (angry?) chorus that habitually sings that spots are being taken away from qualified in-state students whose parents have paid taxes to subsidize higher education.
As for @Gumbymom saying that Cal Poly is still a bargain, she is right. It’s pretty hard to argue with her, in the general. Everybody’s FAFSA/EFC is different, but relatively speaking, Cal Poly is one of the best educations on the market when you do an apples to apples comparison. There are certainly plenty of schools where people can get a great education at a lesser price, but that’s for each person to figure out in the specific.