Politics is about the division of resources, creating and enforcing rules that govern trade, business, education, the provision of services, defence, and the political system itself.
I don’t think you can call politics a necessary evil. Sure it is necessary, but I don’t think it is an evil. When a political system is well designed it works to the advantage of the signatories, and creates a far stronger group than a group of people without a cohesive system to act within. To some extent every nation that has enforced the rule of law rather than the rule of a person or body of people has had great success as a result.
No group of people ever operates without politics. At some stage a decision must be made, and the manner in which the decision is made determines the nature of the political process at work within that group. If the prettiest of the school girls decides where to sit at lunch, that is a dictatorship/monarchy. If the best football players decide the tactics for the upcoming game, that is an aristocracy.
Politics becomes an ‘evil’ when a person has too much power or too much responsibility. Given too much power, they lose sight of their position as a servant of the people. Given too much responsibility, mistakes are made and the population is set up in the fashion of the dream of one person, and therefore lacks resilience. As long as the rule of law prevails and politicians are not swayed by any factor but what is best for the people, politics is a necessary and effective way of managing a group of people.