saying “all powerful” is to say that a being can realize any possibility which can exist. A possibility which cannot exist is like a squared circle. The strawman is that all powerful means to realize even things which cannot exist. In this world there are things which are necessary existence. Meaning they cannot not exist. An example would be the statement “1+1=2” that statement cannot not exist and it is true in all possible worlds. Then you have possible existence such as someone eating an apple. There isn’t anything necessary about it and the person could have very well not eaten it or eaten something else. The apple itself isn’t a necessary existence. Finally, there is an impossible existence. Which would be something that cannot exist like a squared circle. A God which deletes himself or that can create a rock heavier than himself is an impossible existence as it would contradict the very definition we’ve given God. Which is the same as saying A and not A. Or that he can both be God and not God. Thus it is syntactical jargon like a squared circle.