Yeah they should had been if the original formula for partition would had been followed, but they did not so its a moot point. Plus do you see Pakistan complaining about it or raising it anywhere? No. So why bring in something that is neither the issue nor the point of discussion. However you cannot say Kashmir too was India's part because it was not. It has been disputed and your own PM Nehru took to the Security council and resolutions were passed. 4-5 people holding Indian flag in Balochistan does not amount to a protest.
Its staged to score points. . Compare to that the number of Pakistani flags raised in Indian Kashmir.
They are not 4 or 10 or 100 people
Besides when was Balochistan ever considered a disputed territory? Not even by Indian standards. Modi only started recently talking about Balochistan to appease to his home audience even when he was making a complete fool of himself by doing such.
As for the plebiscite when has India ever agreed to one before you talk about meeting conditions. Once India would agree to a plebiscite, the onus of meeting other conditions specially related to that Azaad Kashmir will be on Pakistan. However for that India first needs to accept it as disputed territory which India does not.