Epic Games are infamous for opposing openness in various forms. (Buy these games … only on the Epic Games Store. Install this spyware … no, you can't see the source code. Use any current OS you want … as long as it's from Microsoft.) Supposing that some of the ulterior motives behind this grant are questionable does not seem overly paranoid.

However, I don't see the contradiction in Sweeney's statement. One can appreciate the advantages of open tools, libraries and platforms, and still want to publish a proprietary game on top of that technology.

It's kind of like an omnivore chef joining a forum full of vegans to work on improving seasonings for braised veggies. They might not be pleased when they find out that she wants to make a side dish to be served with steak; but that in itself doesn't mean her goal is exploitation or sabotage, rather than mutually beneficial cooperation.