Total war and seige is this fair

Total war consists of two main details: one, burn everything so your opponent can't use it and two, take all the food and things useful to you. This was used by a Union General  William Sherman. This is super unfair and cruel because in the process of total war they  killed so many people and you should not be able to take others food and burn their stuff down. Siege is also wrong because you surround and then you don't let supplies enter the city or town. These are both wrong war tactics they are not good for the people. These are not fair war tactic no matter what.