One simple question, IDK. Was the bible flood a real, material, global, lots of water and drowned people flood? Or was the bible flood a metaphor, legend, local event that people exaggerated, story-of-Gilgamesh kinda thing?
Because if you truly think that there was a magical flood that killed all humans except one family that survived sealed up with thousands of wild animals on a wooden boat--but that left no physical evidence of ever having happened-- well then we are dealing with a level of credulity that is hard to imagine in the 21st century.
It is best not to try to explain how one family managed to get thousands of animals from across oceans to one location, keep them alive for more than a few days, deal with the water and sanitation issues, return all the animals to their proper habitats while surviving the horrible disease vector that the planet would have become with all the rotting bodies. Just say it was magic, and try not to wonder why god did not just get rid of the evil by magic instead of all the primitive rigamarole of boats, animals and floods.
Besides the scientific and practical impossibility of such a story being real, there is the repellent idea of inflicting massive unnecessary suffering. Yes, I am making a judgement that to drown entire families-- to torture babies, the elderly, pregnant women, toddlers-- repellent.
And so do you, because you could not bring yourself to do it. You are a better person than the god you worship. You can only stomach the idea by making the people into non-humans, evil demons who do not deserve to live. Because that is what Dear Leader said. Kinda like what all dictators do when they want to massacre people.
If god wanted to get rid of people he could just vaporize them painlessly into their next life. Or have the parents of the future evil people never meet in the first place, so they would not ever be born. Or reboot the entire planet with all new non-evil people. Or......use your imagination. But flood the planet and drown all the animals and people? Were even the kittens and baby panda bears evil?
The rabid dog analogy only holds if, instead of killing the dog as quickly and as painlessly as you can, you slowly torture all the planet's dogs to death over several hours, along with their puppies. Because you know that all puppies might become rabid in the future, and you don't want to just give them rabies vaccinations or something like that...way too easy.