It is fair once you know the rest of the story. Once your visa is cancelled the company gets back that visa and will give it to whom ever want to work in the company. if they give you NOC then thee company will lose that visa. The thing is , the company has fixed number of visas. if they lose it by giving you NOC then they lose one visa. if you get banned for 2 years then the company will be able to use the visa again with another person. Companies exist to make buisness and make money. not to distribute visas here and there. then they will be accused of selling them.