Why is the Hated Loved?

[Imladris]

I searched but didn't find what I was looking for. If I missed a topic, please forgive me...

I was reading the Silmarillion and I was surprised and perplexed at the similarites that Gollum, Melkor, and Ungoliant possess:

for she [Ungoliant] hungered for light and hated it.

Melkor does not love light, yet he lusted after the Silmarils (made from the Light of the Two Trees). He would not give give them up, even though they burned his hand:

nor was he ever free from the pain of the burning, and the anger of the pain.

And then there is Gollum, who loved and hated the Ring.

What do you think that Tolkien was trying to say?