This is not my view, its the argument given by PPP and as you mentioned its upto archaeologists to decide whats dangerous for the site. PPP is giving assurances for ‘no damage’ and I don’t think that they would take a risk of destroying these ruins because it will ultimately affect their ethnic card, if God forbid any mishap happens at site.
PS: Sindh High Court didn’t issue a Stay Order and they also came with same ‘if no danger is assured’ type order for the matter and thats why it has been inaugurated at Moen Jo Daro.
PS2: Moen jo Daro is in crtical conditions since long… We have been crying on destruction of Budhas of Bamiyan for long, but no one raised voice for Moen jo Daro. I think its a blessing in disguise that PPP took this decision. I’m yet to see who has to carry this concern in future, as I feel its more about dissing political rivals than actual concern for sites.