The regs are trying to address two main issues.
The O-PEN fault condition is where the protective earth common to most households is damaged and earth starts to float at potentially dangerous voltages. Within the house, if you touch another metallic object, tap etc, that will also be at the same float voltage because they are typically bonded. However, outside, what you touch is likely not to be at the same floating voltage, but at ground voltage, so the difference in voltage between what you touch and what the supply is grounded at could be dangerously high. The solution is to ground sockets of equipment used outdoors (or double insulate) at ground level and not via the house earth, ie metal ground rods. Another solution gathering traction, is an active O-PEN detector that monitors the (earth?) voltage and if it exceeds a certain amount, iirc 80v, cuts the supply and earth. Some EVSE/charge points will have an active device built in. Hence why the regulations is for where the equipment is to be used rather than where the supply is located. One thing to watch out for is that supplies that use ground rods (not sure about active solutions) must not be located where a user can come into contact with other metal objects within the house or an internal circuit.
The main DC issue is that DC leakage is that it can blind other RCD devices causing them to be ineffective. So you can have a fault elsewhere in the house that should have been made safe by an RCD tripping but isn't because the even small DC current is preventing the RCD from doing its job. The solution is a circuit that detects >6mA DC leakage and trips the circuit - such as a B type RCD, although many EVSE/charge points have their own circuit built in.