Because they're the fashion police. ACAB.

I fix cars as my hobby. I don't know about saving the world with it, but it does save a lot of money and I can help friends/family.

However, your criticism draws an interesting point. Working on a car can be satisfying when you're all done, but it's fucking hard work. Hard, dirty, greazy, tiring and many times frustrating. I've bashed my knuckles countless times, stabbed myself on sharp zip ties, burned myself on hot engine parts, gotten oil and filth in my eyes even when wearing PPE. I started doing it because I got tired of being fucked anytime I took my car to a shop and I was too broke to keep doing it. Then I just got used to fixing them on my own and it sort of turned to a hobby. I mean, it's still kind of fun, but most of the time, it's just boring stuff like a radiator sprung a leak and needs to be replaced, not cool or fun like "I'm going to make this go faster, look cooler, etc".

However, it isn't relaxing. I'm tired, dirty and sore when I'm done. Sure, I saved a buck and did it right, but maybe I'm doing hobbies wrong. Maybe a hobby should not have roots in a capitalistic outcome. It should be as enjoyable as something can be, relaxing, stimulating, something you can learn and grow from. If fixing a car is a hobby, maybe cutting coupons is also a hobby--and that doesn't seem like much of a hobby.

I mean, I still feel the same way about adults who play with legos, but maybe I will do less fixing and more music instead.