When you don't understand what God says, but imagine that you are making a point to the arghument, I complain.
Animals do not need to be saved, true. However, they will be affected by the Second Coming of Christ, and we are told by Christ to preach to all creatures.
"All creatures" being the men and women God has created.
If by "creatures" you think God means non-humans, where do you draw the line?
To be consistent with your reasoning, you must also preach the Gospel to gnats, worms, viruses, spiders, raccoons, mice and flies.
Do you preach the Gospel to flies?