The ICC, and its successor under "deregulation" the STB, were never set up to protect the shippers in the first place. The ICC was set up to prevent unregulated competition between freight haulers (initially, pretty much just railroads) so no railroad could get too big a lead on any other. It's the "regulated utility" viewpoint where the company is guaranteed a certain amount of revenue, and even sometimes profit, and the shippers pay what they're told. Staggers modified that to some extent, so railroads are pretty much free to set up their own rates now, and do (to the possible detriment of captive shippers), but the other aspects of the ICC (especially, control of who operates what where) are still around and are under the STB, which still enforces many ICC rules and is governed by ICC precedents.

Again, remember, shippers were not foremost in the thoughts of those who set up the system. So don't expect the STB (as the successor to ICC) to care much about them.