Please stop mentioning that clown Slifkin. He does not have a smicha. He writes because he wants his name to be out there (Look at his 1st piece in Second Focus where he says as much). He also once claimed on the site AishDas in 2003 that the Mabul must be an allegory because the is no evidence that it happened.
Imagine that, he chooses to turn something into an allegory because he does not see evidence that it happened! CLOWN!! AND YOU QUOTE THIS KOFER??
There is a passuk in Reah which mentions about a false profit who makes signs and wonders who says to go against the Torah, the next passuk says don’t follow him. I, Hashem, am testing you. Imaging that Hashem tells us in the Torah that there will be things which come to test our Emunah. No, we wont be able to claim Onus if we fail this test. This is part of bechira. There would not be bechira if those who went against the Torah wouldn’t be able to somehow justify their position.