They can't ban shocks in stock classes.... they're wear items. How can you tell someone with say a 1965 Porsche they have to run "stock" shocks that are no longer manufactured? They're either running 40 year old shocks, or booted out of stock! You could try to say the shocks have to be "of the same specifications as stock" or something, but that's virtually impossible to enforce... how are you going to prove someone didn't revalve them? SCCA would have to start maintaining a list equivalent shocks, and deal with protests involving opening struts to measure valves! With items like brake rotors and springs, simple inspection is usually enough to verify their "stockness" but with struts, they pretty much have to say anything goes. Same deal with brake pads... it'd be way to difficult to make sure everyone is running "stock" pads.
Honestly, I think the Stock classes and Modified classes are the only somewhat logical classes in SCCA. Of course there's dispute as to which cars go into which sub-class of stock, but the rules are at least pretty easy to understand; basically, in stock you can replace anything that wears out... and the front swaybar
. In Modified, anything goes as long as it's safe and meets the power to weight limits.