On top of this, when Thanos turned off the other Gems, he retains his natural powers, which included his cosmic powers of awareness, which is how he reacted to the Surfer trying to steal the Gauntlet from him unless I'm mistaken. Like it or not, Morg was gifted with the same abilities that the Surfer is gifted with, but he still has the WOL in this thread, which makes him even more powerful, as seen when he nearly killed all of the Heralds. I don't see how this is so difficult for you to understand? Gladiator is way out of his league here, even with the blade. He would never get the chance to use it in a non PIS scenario. Why? Because Morg would sense it coming far before it came to some hyper fighting situation.
I'm not saying that the blade could not cut Morg, I'm saying that Gladiator would never get the chance to.