240.4(D) and the previous "dagger notes" to 310.16 were never "without exception". We always had the exceptions now in 240.4 (A)-(G).
I understand that the supposed "hard and fast rule" about small conductors (14ga = 15a etc) is firmly ingrained in urban lore but it is simply not true.
Most notably, most dedicated motor circuits and welders have different rules. It is because of the nature of these loads.
To fully understand this, you need to know the difference between overload protection (provided in the motor or controller) and over current (short circuit) protection, provided by the branch circuit over current device.