What's even more surprising is how many pax react to them as some sort of major emergency. (See any TV news report or newspaper article interviewing passengers after a go around.) It really was necessary to make a reassuring PA as soon as possible.
MTOW,
I disagree with you. It's very unusual event that most passengers will have never experienced. In my 45 years of flying all over the world, I've experienced two go arounds, ironically on consecutive sectors. One was a non-event from three miles back due to a blocked runway, where the captain informed us in advance. The other however was more dramatic - in an MD-80 over the threshold at Heathrow, where we flew into a wake vortex. Full power was applied and we climbed away at a very steep angle. I found the experience very interesting, but I can see how non-pilot passengers would find it frightening.
I do agree that a reassuring PA is necessary.