Destroy in no way addresses the Catalyst's problem, per its own words that the conflict will one day return. I see it simply as a rejection of its assertions without feebly posturing with some kind of spiel about freedom while doing nothing but idling on the platform, waiting for the war to grind to a halt after the reapers win.
I actually disagree with this for a number of reasons. First, what the Catalyst says is that destroy isn't a permanent solution; that isn't to say that it's no solution at all. When you inject botox into your face, you're not permanently solving the problem of facial wrinkles, but that doesn't mean you aren't trying to make yourself look younger when you do it.
Second, if destroy were not at all about the singularity, why would synthetics be the group that's made "hostage" in this decision? You're talking about a group of entities that very possibly could have already been mostly destroyed by the time you got here, so it's a bad choice if the goal is primarily just to make you feel bad about choosing it. The better explanation is that destroy, like the other ending choices, is about stopping the singularity (in fact, you could argue it's more clearly directed towards the singularity than control is, which doesn't do anything to AI's other than the Reapers).
Ultimately, it seems to me that destroy is thematically about the singularity every bit as much as the other endings, and this is so because that is what the game is about at this point in the narrative. A quasi-divine being gives you, The Shepard, an infodump about the fundamental existential crisis of the galaxy (something that's supposed to transcend the Reaper conflict itself) and empowers you to decide how it gets solved. That's the conceit of the ending as I see it, for better or worse.