Why does anyone have a problem with this?
If you don't want to relinquish your idea to EN Publishing the don't submit it. If you feel your idea is amazing and deserves publication then don't submit it to this competition, submit it to a publisher instead.
If I get time I plan to stick to the spirit of the competition, namely writing an RPG in 7 days. I came up with a concept last night and hope to write it up between now and the weekend. Is it original? After a fashion. Is it groundbreaking? God knows. Do I care if Morrus takes it and becomes rich off my labours? Good luck with that.
I have had ideas for ground-breaking RPGs. I have stuff I've been working on throughout my years playing tabletop games. Do I think they'll one day earn me cash? Perhaps. We can all dream. Will I submit any of them to this competition? No, because if I truly believe these ideas are great and will make me rich then I'll develop them and try to get them published by more traditional means.
Do I plan to pluck an idea out of my imagination and cobble it together into something suitable for this competition? Yes. It's a week of my time with the possibility of winning some cash, seeing my idea become a real product, or (much more likely) getting a couple of people say what they think of it.
Where's the controversy in this???