That really makes no difference to the core issue. The point is that even a single attempt at needing an Internet connection, even if it’s just for initial setup, is problematic. Read all of this, in context:
More Ubiquitous Internet Connectivity
With this enhancement, Thread networks will require Thread Border Routers to provide a standardized path to the Internet for the devices connected to it. This assurance of connectivity means product makers can build devices that leverage the cloud for more dynamic features (like a thermostat that responds to weather changes) or give users the ability to remotely control their devices. They can also send software updates to the devices and perform diagnostics to provide better technical support.
With the emphasis on “will”, it seems as if it’s not an optional requirement (it indicates a strong requirement, as opposed to “can”/“may”, which still leaves the door open). Whether it’s standardised in terms of a path really has no bearing on the core issue. Many users of HA, including myself, don’t see any reason that a device would need any form of Internet connectivity, whether it’s for initial setup or continued operation. That paragraph is clearly written from the perspective of the manufacturer and not the end user. The intent with Internet connectivity is made clear in that paragraph. We don’t want devices that have a need to dial home.
Perhaps it’s all badly worded by people not used to writing specifications or standards. Either way, an official clarification would be appropriate.