I don't know if you realize this, but these people are really harming the country's self interest, when they protest their own head of government when he is on a diplomatic mission. Irrespective of your political inclinations, it is wiser not to denigrate the PM in a foreign country. Respect the position, even if you don't respect the person.
If the impression among other heads of govt and diplomats is that your PM does not have the support of or credibility of his own people, why would his words or speeches carry any weight among them? If he makes a speech about Kashmir (as he did), and Pakistanis are protesting against him outside, do you think anybody will take the issue seriously? (Not that the Kashmir issue will be taken seriously by the world at all, but I'm just giving an example.)
Look at the reception Modi is getting from Indian Americans. Now every word that Modi speaks, will be taken to be the authoritative, representative voice of the Indian people. So when he promises to invite businesses and industries into India, businessmen and industrialists would believe him. But when Nazaw makes a similar pitch, he wouldn't be taken seriously.
