I'd hate the thought that I have checked out a book I could otherwise afford to buy and deprived the use to someone that could not. Or that I am using a computer to read Hackernews that an ex-convict needs to use to apply for a government program to keep his grandson alive.
Using the library deprives a slice of the pie to the very people that need it more than you. If you use the library and you can afford the alternative, then you are just as bad as the people that want to close it.