You can change every question I asked to be a moral rather than a legal issue. Why would a well-driven Mercedes with an empty petrol tank, that is only being used within its electric range, be morally less deserving of green power, or be (in your words) less in need, than a badly-driven BMW with a full fossil fuel tank for example?This is precisely the reason why I don't think parallel PHEV should get rapid charging capability. The reason for the thread.
There is no "rule" needed. There is no legal stance needed. There is no punishment required. There is no need to understand car technology.
There is only differences between plug sockets on the cars to distinguish between cars that really need rapid charger to continue their journey and cars that doesn't loose functionality when out of electricity.
It's unfortunate (but expected) legacy car manufacturers are taking this long winded evolutionary approach to electric vehicles. This Mercedes A250e is a sign of what's to come: rapid capable PHEV and confused users thinking all chargers are parking spots. Creating confusion, unintended but undesirable behaviour and slowing EV adoption.
Next we will be saying that cars with built-in solar panels should not have fast-charge capability because they have a second energy source - and one that can be wired serially.
If drivers start to learn how to use charging infrastructure through hybrids, then adoption will be quicker not slower. I believe that PHEV vehicles are a flawed concept and will be gone from the market very soon but they are serving a purpose in encouraging and educating drivers to go electric.