Reasons that people don't like Nicolas Cage broadly fall into two categories; either his habit of not paying tax, or his habit of making terrible films. The two things are connected. According to Cage's former manager, the actor is a compulsive spender who frequently makes outlandish and extravagant purchases on the spur of the moment, which led to him owning 15 different private residences at one point. He didn't keep up with tax payments on any of them, which led to him owing the IRS millions of dollars. As a result, he has to take any paid acting work he's offered - even when the script is awful.
We shouldn't really blame Cage for working hard to pay off his debts; nobody forces us to watch them. He's also probably a nice guy - back when he had money, he was known as one of the most generous stars in Hollywood. In the past, he's donated $2m to Amnesty International, and $1m to support victims of Hurricane Katrina.