Okay, that's cool. I like being wrong, it means I'm learning.
You weren't technically wrong, like I said i dont doubt perlites abrasive, Ive had little cuts all over my arms before just working with the stuff!
But you have to think, in nature theres rocks just as sharp and abrasive as perlite in the ground! And worms are moving all through out those areas! Now earthworms would have the hardest time moving around abrasive soils cause they tunnel and move alot, but when i use to have my own compost bin (years ago) i used red wigglers and you would hardly ever see them beneath like 5inch of dirt. Plus over time they make their own little environment at the surface of the soil. Like the 1 guy that did vermicompost pots had hardly any perlite at the surface of the pot because by the end of flower it was almost all worm castings about an inch deep! Its was crazy! It was the most earthy smell! Loved it!