Question: Why did animals have to die in the great flood?

I don't see any descriptions of giant animals. Beyond that, did not the giant folks actually survive the flood? Aren't they mentioned in Numbers as inhabiting Canaan? Something seems pretty bogus about your interpretation, but perhaps I missed something. Could you expound a bit more on the link between the text and your conclusion.

I suppose, but given the actual process of canonizing, it is difficult to separate out the not inspired from the not included. Sure, Enoch is young compared to most OT scriptures, maybe a couple of centuries younger than Malachi and maybe one or two other OT books, but surely not younger than any NT scriptures.I think it is more telling that Enoch is not considered canon under Jewish tradition, although for the most part, that tradition is scarcely recognizable under the interpretation that most of us Christians give to the Bible. For the sake of a Bible Study thread, I'm willing to at least entertain an argument based on Enoch or Maccabees or other texts. But there still is not much material to work with even if Enoch is considered the truth. Sinning against animals might mean just about anything.