1)
Why does it mention Ona'ah of an Oni?
1.
Radak: This is the normal case. He is weak, and it is easy to afflict him, and [the Rasha] does not fear to do so. He afflicted also others, when he could. Ona'ah is taking others' money in business, with or without their knowledge, like "v'Lo Yonu Od Nesi'ai Es Ami" (45:8), "v'Ha'achalti Es Monayich" (Yeshayah 49:26).
2)
What To'evah did he do?
1.
Rashi: Homosexuality.
2.
Malbim: He approached a Nidah.
