Why are imperialists so mean?

So I began reading a book yesterday that is about India's struggle for independence, which is aptly titled India's Struggle for Independence. And I'm realizing how indefensibly crappy colonial domination is, based on just a few pages of mid-19th century accounts of Indian revolts against the Brits. It pretty much blows my mind that anyone would think it's okay to barge in, take over the land, and then levy taxes and charge exorbitant rent. Then when people can't afford it, take them to jail and oppress them even more. And let's just go ahead and establish a free trade zone and put all of your artisans out of business while we're at it. What the crap?