This is the philosophical equivalent of sticking your fingers in your ears and saying "La La La! I Can't Hear You!" when people confront you with uncomfortable questions about your position. Whether someone is able to make a decree which is itself irrevocable is pretty fundamental to questions of how powerful something is.Thirdly, it's easy to make an entirely semantic argument that these puzzles just don't mean anything. Saying that God can't make a really heavy rock is equivalent to saying that God can't make a square circle or a red green thing: they're just nonsense statements that don't mean anything at all. I don't have enough of an understanding of philosophy of language to expand this further (the verifiability criterion is about as far as it goes), but that's the argument broadly construed.
If a being can sign a contract that is binding to itself, then there are limits to its power. If it can't, that is also a limit to its power. Either it has the power to make inviolate contracts or it has the power to unilaterally change the terms of its agreements, and it can't have both! The unliftable rock is merely a philosophical stand-in for a permanent and binding agreement. So if the god in question cannot create a rock that is too big for it to lift, it cannot be trusted.
The Christian god in particular seems to be unable to create a rock too big for it to lift, as evidenced by the fact that it changed all the rules in the New Testament. There is nothing stopping such a being from giving new revelations to Mohammed or Joseph Smith and completely changing all the rules again. There is no point in following your terms of a contract with such a being, since if it wants to pay or punish you in the future it simply does, based on whatever it happens to have amended the contract to at a later date after it's too late for you to do anything about it anyway.
-Username17