Benevolent: "(of an organization) serving a charitable rather than a profit-making purpose."

That's not how this word works. We can use another one.

I hasten to add, again, that I'm attributing nothing pejorative. I'm glad Epic have done this. It's great marketing that may be helpful to lots of people.

"benevolent" wasn't being used to describe the organization, it was being used to describe a particular action.

The issue is this action isn't benevolent. It's nice, but as said previously it's to promote their engine. So they will profit from it indirectly.

If on the other hand they would release the assets without strings attached (for use with any game engine / in any way) then I'd say this word would apply.

and my point was that this seemed like a false dichotomy.

True. A dichotomy cannot explain for example tax deductible donations: they're obviously self advertising at much lower cost than a real PR campaign, still they benefit someone, so we probably should use a trichotomy like "I'm doing good even if it has a sustainable cost" - "I'm doing good only if it somehow benefits me as well" - "I'm not doing good because being evil brings even more profit than the above".