Yes, but the PM is the head of the govt and has certain executive powers, you can't possible make out that being a PM is insignificant/irrelevant in India. All democracies have cabinets.
Not all democracies, only the ones that follow the westminster system.
The PM has executive powers in principle, but in reality, actions are always taken collectively by the cabinet of ministers. They are answerable to the party. It is the party that makes the PM, not the people. The party can control the decisions of the cabinet.
Most decisions, if not all, are taken collectively. I cannot recollecct any instance of a PM unilaterally taking a decision or exercising his executive powers without the backing of the cabinet. All executive actions are done after a cabinet meeting.
There is a more fundamental reason why the US politicians have to talk about their global views. The Foundation of the US economy is the almighty USD which is hedged against Oil forcing all nations to buy Oil in USD. They ensure this by having a military base in most oil producing nations and declaring others as part of "axis of evil". For any US politician to talk realistically about US economy, he should to have a firm grip on Global scenarios.
Indian politician suffers from no such compulsions and is free to look inward and focus on what is relevent to the Indian public and not to media houses.
You are tlking about the issue of why US presidential candidates are expected to talk about their foreign policy and even military views, but Indian politicians are not. That is true, but my point was about why Indian politicians do not have to voice their individual views at all, about any issue - it is the stance of the party that matters.
For example, if the declared stance of the BJP is that they will not allow FDI (I'm giving a hypothetical example), then Modi will not declare that if he becomes PM, he will change that. They always speak about what the party will do when in power, not what an individual will do. OTOH, during the presidential primaries in the US, the contestants within the party often have differing views. McCain wanted the troops to stay in Iraq for a hundred years if necessary, Ron Paul declared he would bring them back the next day, Mitt Romney had other ideas...
So in the USA, the question that the politicians address is what they will do about something when they become president or governor or senator. But in India, the question is usually what the party's stance is.
In my opinion, each system suits the respective country.
Coming to the particular question of foreign policy, obviously the US influences globa events much more than India does, so the president is expected to hav a firm grasp on those matters. For instance, the presidential candidates will be asked questions about whether to continue drone strikes in Pakistan, what they will do to help the afghan govt, what their midle east policy is, whether they would support the syrian insurgency or not, whether US sould continue selling treasury bonds to China etc - but the questions we would ask our politicians are mostly about domestic issues, with the possible exception of terrorism emanating from neighbouring countries.
