Not discounting the negative effects of the nationalism, but I don't think caste system is behind the current rise of nationalism. The prime minister himself is from the lower caste.
Would it surprise you to hear that there are many women in India who support for existing misogynistic aspects of traditional culture?
It's hard for people to understand how deeply woven caste-based motivations are in Indian society. At a large scale it may seem like some globally stratified layer cake. On the ground, it devolves into regional tribes.
The "caste associations" rural people associate themselves with in rural areas are loosely formed tribes of 10 thousand to 100-thousand strong members.
The perspective of many who choose to be invested in this system - which is most people living in those areas (what else are you gonna do? not support your tribe? who else is gonna have your back if there's trouble?) - is one of trying to gain status for their caste/tribe over others.
Caste rivalries are often regional, and localized.
Identifying India's current PM as not coming from one of the well-recognized "higher castes" is really meaningless. It'd be sort of like saying "yeah, this politician is unlikely to be a hardline christian dominionist, he's a 7-th day adventist, which is clearly a minority sect".
I agree with you on all the points except the last and in no way I am saying the there are no caste based discrimination in India. In fact caste based discrimination and the effects of it is one of the main reasons of India being "developing country" forever, I think.
My point is that the current rise of nationalism is not because of the caste system, but rather in spite of it. I see many people from lower caste(including my relatives) being active in the local rightwing politics and RSS.
If you are still not convinced, look at what "Subramanian swamy" had to say when every one in BJP party was changing their twitter profile last name to "chowkidar"(meaning soldier or protector). He said he is a brahmin and its brahmins duty to advice how the country should be run and not be a soldier as vedas consider brahmins as superior to all the other varnas.
Subramanya Swamy is 81 yrs old. A person who has remnants and values of old-school of casteist thought.
I don't expect him to be post-modernists egalitarian.
However at the same it doesn't mean he can't say his casteist comments openly. ;)
After all, its better if people say it openly so that they can be criticized for their casteist comment. The likes of him is politically insignificant as he is NOT competing in elections.
Subramanian Swamy always denounced birth based caste system and always said anyone with 3 qualities - knowledge, sacrifice, courage should be considered as a brahmin and he has also said in many places that as per this Dr.Ambedkar is a brahmin and Nehru is not.
Modi himself added his trader community to backward caste for reaping benefits while he was running for CM of Gujarat using BJP govt at centre. Modh-Ghanchis are a middle caste which is a beneficiary of caste system and is by no means an OBC.