So to make your hurricane analogy more specific, let's say he's like someone from New Orleans who lost his family to the floods during Hurricane Katrina, blamed the FEMA director for failing to prepare adequately, got arrested and spent 25 years nursing his grudge in prison, and then made the FEMA director watch while he flooded the director's home city in retaliation. (Well, the FEMA director at the time was born in Oklahoma, so maybe flooding isn't a likely option, but hey, it's a hypothetical.) Not the most rational response, but not random either.
Maybe not random... but still kind of unstable, yes?
(And even with the revision above, I still think "nuking Oklahoma" would be a better analogy than "flooding Oklahoma". In the movie, Nero didn't really make any attempt to have Vulcan suffer the same type of destruction as Romulus did. He basically just dropped a WMD onto (well, into) it.)
But if the red matter came from the Federation, and he destroyed the Federation, then this timeline's Romulus will still suffer the same fate. More evidence of Nero's instability.There's also the fact, of course, that Nero was back in time. He blamed the Federation (irrationally) for Romulus's destruction, and being in the past gave him the chance to destroy the Federation before it could destroy Romulus. Maybe he didn't realize it was a separate timeline, or maybe he wanted to spare this timeline's Romulus from the same fate as his version.

Nero is looking for understanding and empathy, really. He needs his former friend/respectable acquaintance to know his pain.
I'm asking because I honestly don't remember... is there anything in the movie itself that indicated that Spock and Nero even knew each other personally? I thought all the "Spock and Nero are friends" stuff came from Countdown.