You can read the current and previous versions of the NEC by going to the NFPA website (https://www.nfpa.org/codes-and-standards/). The NEC if document NFPA 70. You need to register with the site and give them your email in order to use the free access viewer. The viewer is awful too. The 1996 code doesn't have a table of contents, so you start at the front or back and hit next or previous page until you get to where you want to go. The 1999 edition, you can click on switches in the table of contents and it takes you to article 380.
The requirement to ground switches (which is to provide provisions for grounding metal faceplates) was first required in 1999. In 1996 and prior, it was only required if metal faceplates were installed. The relevant article for switches was different in 1999 - article 380 instead of 404 in the later editions.
I can see electricians missing things the first year it was in the code, especially if Continuing Ed is not required to renew their license. But it had been in the code for 6 years before the 2005 edition, so they should have known. Conversely, it is easy to miss little additions to the code the first time they occur if you didn't look at all the change bars the year it happened. So if they had old electricians they were probably used to not grounding switches unless they were in a commercial setting where metal faceplates were more common.
Note that "a nonmetallic box with integral meas for grounding devices" means there is a metal rim in the box that touches the switch or receptacle mounting yoke and the ground screw in the box connects to this metal. You sometimes see this on round light fixture boxes, but I've never seen a plastic device box with that feature. The NEC is full of references to devices that do not exist (the manufacturers try to get things mandated or allowed to support things they have invented and want to sell).