I wear one because my glider handbook says it is required or I must
fit some additional cushion in the seat back. Given the choice
between a piece of safety equipment or a piece of foam, I will take
the safety equipment. Remember, the unlucky pilot is one who has run
out of Altitude, Airspeed and, Options. The parachute is just another
option!

If you extend your logic (which I will agree may have some degree of
truth), then I drive my car differently because I wear seat belts and
have airbags. Accidents are accidents and I am quite certain that we
all strive to avoid them, parachute or not.