This kind of behavior where people are labeling anything and everything racist is very much harmful, and makes every sensible people less sensitive to racist claims.
1. In lots of places most manual work is done by white people, who as I've heard can't be targets of racism.
2. Manual labor can be a very well paying job.
I did manual labor for a while, and guess what: my clothes sucked too.
No laborer is going to get offended if you tell them that their clothes are not good looking.
Stop getting offended in the name of a random group of people.
Not many "work pants" even have cargo pockets,
I think it’s fair to characterize them as faux-workwear, for the most part. Some folks can get away with them and do wear them because they’re cheap and easy to find, but anyone who really wears their work clothes will usually go for something else. Doing handyman stuff around the house, fine. Framing houses, you’ll be shredding a pair every few weeks, and some you’ll probable rip at the seams the first or second wear.
I manage tradespeople and go to job sites often.
Cargo pants to me are an unfortunate holdover from the 90s fashion worn by people who don’t particularly care about how they look. People wear clothes for various reasons, including utility.