It's color theory. All schools that have any semblance of creativity involved teach it. You're calling it crap because you see it often, but it's actually based behind the actual theory behind complementary color use. It's effective whether you like it or not.
That being said, this cover art for Fuse is a complete joke...and not just color-wise. The composition is absolutely horrible. Their crotches are the CENTER OF THE COVER...why is there so much empty space below the picture?! Why does nobody have a face! It's deliberate but it's not good design.
I think the cover wants us to focus on their weapons
Problem is that they're glowing the same color as the background of the box, so your eye isn't even drawn to them at first glance, but rather to the floor.
and even when you do notice you're not even sure what you're looking at. Especially with Dalton's weapon which is almost completely obscured by its glow.(I thought it was the Sun the first few times I looked at it)
It definitely needs a redesign
or not I guess. It's definitely loud enough to draw eyes browsing any store shelf