"Are you trying to tell God how to run the universe again?"
Yes. Got a problem with that? Are you God?
"AND yes he could have used some different way."
Yes. As in he could have just as easily poofed all those 'unrighteous' people out of existence, as he did poofing into existence this universe, this world & all the life on it. Or is God not 'omnipotent' enough to have done that, hmmmmm?! If he couldn't have done so, then he's not God. Your call.
I suggest you visit Tv Tropes, Velma, and search for the term 'Fridge Logic'. It exists for a reason.
"He put the rainbow in the sky as a promise to never flood the earth again."
So, for all those years before said 'Flood', it never rained anywhere on that world. Ever? Like I say, Velma: 'Fridge Logic'. We Atheists has it. Did you Bronze Age goatfuckers with ideas above your stations?
...besides, that first rainbow only proved that God had turned hyper-homo, and was having extremely gay sex at the time. >:D
"It will be fire next time."
So you worship Odin? It's Fenrir who will consume the world with fire, as part of Ragnarok. [/smartarse]