The Tempest

I remember reading this long, long time ago, and being enchanted by it.
Now... I find it rather... nasty.
So, Calaban's “crime” was to not want to be a slave on his own island, given to him by his mother, and falling in love with Miranda? Oh, and being ugly. So... let me guess... he was black.
Also, they SAY Sycorax died long before Prospero and Miranda arrived, but why, then, would Prospero have taught Calaban the names of sun and moon? More likely Prospero killed Sycorax when Calaban was still very young. What ever.
I am also uneasy with Ariel. “Just do this one thing, and you'll be free”. Over and over again. And why wasn't she free to begin with? Because Sycorax enslaved her? So Prospero just took over the slaves after Sycorax? So... how was he being this kind and enlightened regent?
Uh. Leaves very bad taste.