We rent an apartment in Catholic Goa, and have been into neighbouring Karnataka and several occasions. Although the people are generally decent and friendly, there is a small but nasty element, some of who are members of the RSS. These induviduals want no foreigners in India, a Theocracy where the Saddhus make the laws, the ancient Sanskrit language and calendar, and the banning of all modern technology. You get the picture. I have to stress they are treated with contempt by mainstream people, and I never had any mither from them, but visitors to India should take care when travelling of the tourist spots into, isolated villages.
You are right in your characterization of RSS. They are indeed a dangerous fringe element and are anti-foreigner. They are shunned by most of the Hindus in India and should be avoided by visitors. On a violence scale however, your local rag-tag Palestinian militia would put them to shame.