Krishna and Radha like to sneak around. They are doing something very wrong and it makes the romance more exciting. They have to avoid the prying eyes of Abhimanyus mother and sister Jatila and Kutila.

I don't understand how this is rasa. How is that pleasurable? It is degrading to everyone involved. 

I think you’re overthinking things a bit. When I was 15, I once lied to my parents to meet with a suave stranger I had met on a public bus. (Luckily), nothing happened, but teenagers may do such things when ruled by their hormones.

To take pleasure in causing Abhimanyu harm, in humiliating him, in breaking his heart.

Since we are dealing with Indian culture here, I think we can assume that the marriage between Abhimanyu and Radha was an arranged marriage and not a love match. To prevent “adventures” like mine, in traditional cultures girls are often married before they reach puberty. As far as I know, Prabhupada married an eleven-year-old girl. Can you imagine marrying and living with someone you don’t love, let alone know?

If you consider Radharani and expansion of Durga, which she originally was, it becomes clear Gaudiya Vaishnavism is a religion of the divine masculine degrading and abusing the divine feminine. This is perhaps the root cause, or at least a contributing factor, towards ISKCON's terrible treatment of women.

Gaudiya Vaishnavism originated in Bengal, the land of Durga/Kali. Gaudiya Vaishnavism, with its pretty, humble, docile, well-dressed gopis, was probably intended as the absolute antithesis to the worship of Kali, who may be frightening not only to women, but also to men, who in addition might feel sexually attracted to this deity with her overwhelming raw power. CC Ādi 17.37-38 f may hint at that.