The paint requires time to finish curing and in order to do this it has to be able to outgas. This takes an extended period of time and if it is not allowed because a car is waxed too soon the paint neve hardens correctly and will swirl *much* easier from that point on.
Also, fresh *lacquer* repaints can take quite a while to harden enough for final abrasive polishing. Regular b/c hardens up quite a bit faster but are still quite a bit softer after one day than they are after three weeks.