They're just doing as they are told - front-line 7/11 employees do not make the rules and quite understandably do not dare not to follow them (why would you just because you think they should?). Any telco/internet connection in the country requires original ID for Thais and original passport for foreigners in order to set up - has been like that for years.

What is bizarre though is that it has become required to provide ID/passport when topping up your Rabbit (BTS) card at a ticket office!!