I guess it depends on airport size, passenger load and availability of screening technologies. The article you posted is somewhat accurate but also misleading.

Every checked bag is screened before being loaded aboard a commercial airliner. Is everything screened by the CTX? No. Do they have to be? No. There are acceptable alternatives that allow us to screen items other than CTX.

However, if we were to screen everything through the CTX, then you would either have flight delays or simply have some bags that wouldn't be loaded aboard your aircraft.

Again, this is a matter of risk management versus risk avoidance.