liability of share holders on writing off the company by ROC

according to companies act 2013,chapter 2,section 7,it provides that if ROC comes to know of any fraud or wrong information provided to it in past and if it comes to know of it after the name approval and incorporation of the company.It may strike off it's name from register.and the liability of the company shall be passed on to the shareholders making them unliable.why r the BOD not held responsible and since the company has it's genesis from the promoters it's them who has plotted the fraud as they r people who made everything before the company is incorporated .but here shareholders are held responsible.why is it so?