I don't see what difference having a red background for RPT or grey background for GA would have achieved. All rhetoric and semantics aside, the card's primary purpose is to identify people who a. Have a legitimate reason to be airside at a security controlled airport and b. Provide evidence that that person has undergone security checking. Those two criteria on their own are not bad things. The costs and delays however in obtaining the damn things are certainly reason for complaint.
Even a grey card for landside security areas of an airport involves the same checks (and therefore costs). The difference in colour is just a means to stop people who don't need to be airside from going there.