First, the OP's rant aside, NEC does define a "continuous load" as any load that is connected to a plug-and-socket connection for a period exceeding 3 hours. (article 100 definitions)
Second, the NEC requires that a circuit breaker be rated at 125% of any continuous load that may be connected to it (210.20A), which means that a branch circuit with a 15A breaker may only support a continuous load not exceeding 12A.
If a Tesla is plugged into a socket for more than three hours, then it may not draw more than 12A continuously, regardless of voltage or power factor. So, this calculation must be done at minimum grid voltage and actual power factor.
The US national power grid service specification is 120V +/- 5%. At the minimum voltage of 114V, and assuming perfect power factor, a 1.4kW load draws 12.28 amps, which exceeds the continuous load limit for a 15A branch circuit.
It is therefore a violation of the NEC to leave a Tesla plugged into a wall socket (dedicated or not) for longer than 3 hours if it is drawing 1.4kW that whole time. (It is also a violation to leave a space heater on 'high' for longer than three hours if it is drawing more than 12A).
Also keep in mind that the limit is 12A, regardless of power factor, so really if the Tesla is drawing 1.4kW and the power factor is not corrected, its current consumption may be considerably higher.