[zematis]

> ... I know this does not justify anything

> ... wouldn't it be acceptable for humans to do the same?

Edit: Re-reading your comment, I think this isn't a charitable interpretation. I'll assume that you don't think cruelty in nature justifies human cruelty unless the animals are knowingly cruel.

I still don't agree with you however. I don't think it's acceptable to wrong someone/an animal just because they knowingly wronged someone else/a different animal.