User, in general the Islamic groups get the press coverage as they tend to undertake the most dramatic attacks, but also due to the wider Islamic groups and the fact that these tend to be international in nature.
Whilst it may be true to say that the Hindu groups are more Political than Religious, the same is equally true of the Muslim groups operating in Kashmir.
The West has a blinkered view of Terrorism due to the fact that the vast bulk of actions undertaken that directly effect the West or Westerners are by Islamic groups. The Hindus, Siekhs and other groups tend to operate onlu locally, and generally this is in areas not on the tourist trail, as a result te West is largely blind to the fighting. The Main Hindu group was founded in 1966 and has direct links to a major Political party in India, they are called the Shiv Sena, they have also created a sister group in Nepal, Nepalese Shiv Sena.
This is equally true for the forgotten religious war that has been ongoing in Myanmar (Burma) for well over 40 years where the indiginous indians in the North of the country have been systematically butchered by Government Troops at every opportunity. These people have fought the Government and yet the West is largely ignorant of the conflict. The argument the Government used in Myanmar is that they are Islamic trouble makers trying to undermine the nation. In reality these people are not Islamic, they have their own indiginous belief system, if I remember correctly it is distantly connected to Buddism, but I could be wrong on that.
You would probably be surprised to hear that there are as many Christian based Terror groups listed by the UK and US Governments as there are Islamic, in fact the US State Dept lists more Christian terror Groups than all other Religions combined. To be honest most are US based Race Hate and White Supremecist groups, but also there are home grown groups listed here in the UK, as well as many other European Nations. Most are inactive in the sense of Islamic groups, but they are active in creating Civil unrest, letter bombs and Hate crimes.