>It’s literally calling the man “selfish” for refusing to allow others to profit from his work.

If the object was to prevent others —— i.e. the syndicates who helped him develop the comic strip and helped to promote and distribute it —— from profiting from his work, why wouldn't you call this selfish?

Bill Watterson chose to syndicate "Calvin & Hobbes," that is, he chose to sell it, so he fully engaged in capitalism. He just didn't want to profit (or let others profit) from it in other ways, e.g. selling plushy toys etc. But he profited enough from newspaper syndication and book publishing to retire at 35.