I think the "problem" is that people keep thinking Hulk busting a planet is the most impressive thing about the HOTM feat. It's not. The fact that the collision disintergrated an amped Bi-Beast, amped Wendigo, amped Fin Fang Foom, Armeggedon and an army of Mindless Ones so vast Umar couldn't stop them, is.
To put it into better context, let's say Superman and Captain Marvel collided in midair. The resulting shocwave causes Wonder Woman, Aquaman, Steel, and Captain Atom to explode. Would you think that Superman could beat Darkseid?