It is just a myth.
One can harm Pakistan without dual nationality.
It is just a myth that dual national citizen, especially a PARLIAMENTARIAN can be a SPY of CIA or MI6, etc.
UK, USA etc. can give special privilege to there agent, that is not dependent on dual nationality.
Aslam Baig, Hamid Gul, etc. those who made IJI were not dual nationals.
Nawaz Sharif PML-N, Qazi Hussain JI, etc who joined IJI were not dual nationals.
Those who took money from ISI were not dual nationals.
Those who waved off loans are not DUAL NATIONALS.
Even if it becomes law, it will not make any difference.
Just like the gimmick, official name of our country is "ISLAMIC" REPUBLIC OF PAKISTAN.
Arsalan Iftikhan and Malik Reyaz issue are not because of dual nationality.
Those who took Rs25/Kg Sugar to Rs.125/Kg and they are in NATIONAL ASSEMBLY are not dual nationals.
Sugar cartels are not dual nationals.
SRO culture in 90s during Nawaz Sharif govt are not because of DUAL NATIONALS, etc.
Hameed Gul sent Imran khan to Edhi to get help to topple the govt. of BENAZIR. Both are not dual nationals.