I can totally see where you're coming from and in some ways I feel the same.
However I think the disaster being a squid is right because it is ridiculous. Ozy claims to not be apart of the stereotypical superhero/supervillian archetype, he wants very badly to do something grand that will make the world a better place.
He wants change very badly but along the way he falls into the exact sort of behaviour he was trying to do away with.
His plan was corny and bizarre and, in the long run, really impracticable. It's a temporary victory at best, all in another in a cycle of atrocities commuted to prevent atrocities by people who thought they could be heroes.
A big blue explosion is clean, the result of Ozymandias's plan is messy and undignified. In the comic the people didn't get a quick death, they were mutilated by the grotesque brainchild of a man in tights.
Our politics, wars and personal struggles are tragic. But tragedy is also inherently silly and that's kind of sad.
Superheroes are very silly but we still love them and we want them to be real very badly and because of that all sorts of terrible things happen.