A spin isn't exactly a violent manuver. The thing that freaks people out is watching the nose come down through the vertical, and, as was pointed out earlier, the control force needed to keep the "vertical snap roll" going. There's essentially no G loading except on the recovery, and correctly done, this should be well under 2 g.
In planes that WILL spin (like Beech sundowners, Citabrias, and Stearmans, to name a few) it's disconcerting that the pilot has to DO something to "Make It Stop!". Now, that "something" is generally fairly simple, but it's not initially intuitive. If we don't teach it, MOST of the people who end up in the situation will not be able to figure it out for themselves before they end up dead.