I've always felt drawn towards the values of ownership and possession in relation to love. The idea that love means belonging to each other, in real ways you will be mine and I will be yours, is beautiful to me. I think some people are confused as to why Greg is happy to be Tom's Sporus, but what they need to understand is that Tom makes Greg feel loved. 

You're mine and I take care of what's mine. You're not nothing-- you're more than a sprinkle to me. 

I don't think he's truly dehumanizing Greg or only valuing Greg for his usefulness in the sticker scene. Not even 24 hours before, Greg jeopardized Tom's place as CEO. He's clearly not helpful to Tom so there's no corporate advantage to him sticking around. The motivation has to be purely personal. The stickers were meant for objects you covet. He sees Greg as his: my piece of shit, you might be an asshole but you're MY asshole.