1)
Why does it say "va'Yiznu"?
1.
Radak: This refers to Arayos.
2)
What are "Ma'aleleihem"?
1.
Malbim: They are actions that come from natures of the Nefesh. They did not repent from the deeds, until it became their nature to pursue Zenus, murder and every bad Midah. Sins with a root in the Nefesh are worse.
