Not the socket’s fault; it’s the charger. My MBP 90W charger doesn’t have a grounding pin. The 60W doesn’t have a grounding pin.

They have the hardware to be grounded (the metal T stub on which you attach the local plug), but they don’t come with the extended wire by default which has the grounding pin for the outlet.

In actuality, the reason you feel the tingle is because the case is effectively grounded to the neutral pin. The three phases are joined together at the transformer to create a cheap neutral, but because the load on all three phases are slightly out of phase, our body can feel the handful of mV being leaked.