I already said the Peta ad is idiotic...

[Silent3]

...so I'm not defending Peta at all. I think they're zealots who do their own cause more harm than good.

I hardly want to stand in the way of anyone making fun of Peta, Ted Stevens, or anyone else richly deserving ridicule. However, if someone had played Captain Obvious when talking about Stevens, and said with great disdain, "The internet uses SOLID wires, there's no hollow space inside, so it can't be tubes!", I would have jumped in to say that Stevens analogy wasn't all that bad, in and of itself, for certain limited uses.

What spoils such analogies for both Peta and Stevens is inept bumbling usage of those analogies. In Steven's case, he seemed so clueless that you had to wonder if he might have literally meant tubes. In Peta's case, I don't think they're deliberately misrepresenting the biology, they're just so determined to go for the gross-out factor that they're playing up a loose analogy like it's a much stronger one.