I'd have laughed at him too. To think that the person who created violence, is claiming he'll use violence because he's angry that the violent things he created are violent... it's all laughable.
If all the carnivores couldn't exist at this time, then how did they come into being?
God said to the HERBIVORES "I don't like your violence".... and then in the 6,000 years since he's done NOTHING about all the CARNIVORES kind of suggests your theory is WRONG.
The problem with your Isaiah part is that it talks ABOUT THE FUTURE.
"will" not "did"
Literally I showed you the part of Genesis where it talks about EATING ANIMALS
"Take with you seven pairs—male and female—of each animal I have approved for eating and for sacrifice,[
a] "