I can understand all your feelings except one. " in my state kerala the communist ministry is discussing about opening temples to all citizens"
What is wrong in it. Then again you complain that hindus are converting. You do not allow people to worhip at the same place. You do not allow them to have religios equality and then you again cry when to get converted.
Why those people would convert if you allow them to worship at the same place, Think why you do not want to convert, find the difference and see where these people stand, you will get the answer yourself, why there is a threat to "hindu religion"