I don't see anything wrong with selling it. They don't give away clothing like this for free IRL. You try going to a rally some time IRL and telling somebody off for selling t-shirts with slogans on them.
This merchant took time to make that hoodie. They do deserve something in return for it. I mean, putting it out for free would be great but expecting it to be free is like telling the creator that their time is completely worthless.
This merchant isn't going to retire on selling L$50 hoodies. It's $0.52 US. That is way below what the cost of his time is worth, probably, unless he's selling insane volumes of this hoodie.
Anyway, I bought it and plan to wear it. Thanks for the link, Pancake!