Muscles and testosterone don't help much in a sport that demands subtler violence. Only precisely performed techniques exact a choke or tap out, snap a limb or joint. Martial Arts and Boxing rely on highly stylized drama as much as skill.
Wrestling requires strength more than technique.
What this means varies. Grapplers chip bones, pop ribs, break limbs, crack noses, dislocate elbows, and separate shoulders. They face their fears. They face each other. Picture the risks of not fighting.