Different opinions on what is causing it. Who is first in filing a patent describing how to get rid of this nuisance, save people's money plus the environment, and becomes a multi-millionaire themselves :)

Isolate the problem, find the solution, run to Shark Tank/Dragon's Den!

I have found that my shirts were getting holes in the armpits area, and I discovered that the drying rack is causing this. Since then I use 2-3 racks/'lanes' per item, so the weight of a wet garment is spread out and also helps the garment dry faster since air can circulate. I also make sure the armpit regions of the t-shirts aren't right on the wire but a bit lower.