I would imagine that the texture creator was asked after the fact, not before release.

So you've got one person who invested a lot of effort releasing a product, possibly their first one, and the original creator not happy that they created something for profit that support their character.

A sticky situation for both parties.. especially if the texture creator is doing this to put food on their table, or helping to support their family.

Way too many people take way too many things way too seriously.