The point of it, in the Catholic tradition, is not just some sort of general "service" or "just be nice to everyone" moment, but it's specifically tied to the commissioning of the apostles and the institution of Holy Orders, as a institution of *service* to the Church and one whose members are called to be *servants* to the Church, and, in a particular way, to each other.
Which is why it is wrong to wash the feet of women; it's tantamount to ordaining them. The Pope doesn't understand this, or simply doesn't care.
Was foot washing a pre- or post- Vatican-2 practice?
I’m ‘only’ 53 y.o., so I don’t remember.