How is Caliban portrayed when he says "then I love thee" in The Tempest?

Caliban is portrayed sympathetically when complaining to Prospero.

When Prospero landed on the island, he enslaved Caliban through magic.  Although Prospero treats Caliban with nothing but derision, when we first meet Caliban we are more likely to feel sympathetic for him than for Prospero, the vengeful wizard.

Caliban makes it sound as if Prospero tricked him, being nice to him at first so that he would think the wizard was a nice person and then...

Caliban is portrayed sympathetically when complaining to Prospero.

When Prospero landed on the island, he enslaved Caliban through magic.  Although Prospero treats Caliban with nothing but derision, when we first meet Caliban we are more likely to feel sympathetic for him than for Prospero, the vengeful wizard.

Caliban makes it sound as if Prospero tricked him, being nice to him at first so that he would think the wizard was a nice person and then turning on him.  Caliban gives examples of the nice things that Prospero did for him when they first met. 

When thou camest first,
Thou strokedst me and madest much of me, wouldst give me
Water with berries in't, and teach me how
To name the bigger light, and how the less,
That burn by day and night … (Act 1, Scene 2) 

Caliban says that he loved Prospero, and showed him “all the qualities o' the isle,” such as where to get fresh water and food.  He continues by saying that if he hadn’t, he would have been the king of the island, not Prospero.  Prospero doesn’t buy it.  

Thou most lying slave,
Whom stripes may move, not kindness! I have used thee,
Filth as thou art, with human care, and lodged thee
In mine own cell, till thou didst seek to violate
The honour of my child. (Act 1, Scene 2) 

He accuses Caliban of trying to rape Miranda, and says that he deserves nothing more than harshness.  It is better to whip him than be nice to him.  From this point on, we might feel more sympathetic to Prospero and no longer for Caliban.  The comment about Miranda makes Prospero’s harsh treatment of Caliban seem appropriate and justified.

There are two sides to any story.  It seems that at first Prospero and Miranda were nice to Caliban.  He showed them around the island, and they taught him about the world.  Caliban says that they taught him language. Then, at some point, Caliban might have made a move on Miranda.  That was the end of the kindness, and Prospero treated him with scorn and punishment thereafter.