The alternative to government, being nature, where the strongest rule is what makes it necessary. But its ability to deprive its subjects of life, liberty, and property is what makes it evil. If its treated by its subjects as though it is evil, it is limited. But when its subjects trust it, and give it more power, is when its evil grows. In it's ideal I suppose it's not evil, but I think we can only get it close to being ideal when we start from a baseline that it is evil.