It looks like you gave up, OP. But if you didn't here's my criticisms:

You posit that if humans are mentally superior to animals and if human life is greater than animals life, then it is ethical to eat meat.

How does being mentally superior and valuing human life lead to meat eating being ethical?

A common hypothetical argument to point out why this is a bad argument is the alien argument. If an alien is mentally superior and an alien values the life of their species over the life of humans, then it is ethical for the aliens to eat humans.

If you disagree with aliens being allowed to eat humans under these premises alone, then I think you can't say that humans should be allowed to eat animals under the same premises.

Your second argument doesn't really seem worth mentioning. If I deciphered it correctly you are saying: If humans are held to the same moral standards as meat-eating animals, then eating meat is ethical. I think almost everybody would agree that humans are held to higher moral standards.

A common argument against this is: anything animals do to each other, we are allowed to do to each other.

If you don't like that, then you should change your second argument. If you have no issues with it, then I'll concede. It's a perfectly valid argument.