Animals were being killed before the Flood, but not eaten. Why?
Seems like a waste to me.
Jehovah did not say you can not eat flesh. (I think) He just said you can eat vegetation.
Why did Jehovah give permision to eat flesh after the flood ? I think it was because flesh was being eaten anyway.
Animals were not in fear of man before the flood, after the flood they were.
Jehovah gave animals some instinct to survive from all the hungry humans, and now he figured the animals had a fair chance.