This article is a load of bullshit.
S2000 regulations are the closest to the spirit of touring cars: cars derived from a production example. Old DTM, old BTCC, old TC2000, WTCC, with which the concept "touring car" was born, were all derived from production cars. Nowadays, "touring car" is just a phrase thrown by the promoters to name a series.
I don't consider modern DTM a "touring car" championship, despite the "Tourenwagen" in the name. Those cars are almost prototypes, they're faster than GT cars, when it should be the other way around. TTA, Stock Car Brasil, NASCAR aren't touring cars as well.
Now what happens next, let's enter a tube frame prototype in GT, have it FIA-approved and call it a "grand touring car"...