Explanation of "Eagles may soar, but weasels don't get sucked into jet engines"?

I'm proofing some letters written to soldiers by kids at my school to make sure they're appropriate/positive, and somebody wrote "Here's a picture of a cactus with a sombrero [accompanying a picture of the like]. Eagles may soar, but weasels don't get sucked into jet engines." No name, thanks, etc. Discard?