You said you are a tamilian. But I could not find any evidence to that. So I conclude you are not a Tamilian. You may not even be an indian(I do not have any evidence for that too.)
Your argument of saying Ram Setu not man made is nothing different from the argument above.
I am a Hindu Tamilian too. Just because some Karunanidhi or Jayalalitha follower says it is not man made it can not be true.
I do not need any evidence. Its my faith that it is Ram Setu and any disrespect hurts me like many more Hindus all over the world.
But I am not against any developement project, for hindus the whole universe is sacred. So for many people who believe in Ram Setu, finding a solution to continue the project without any major harm to Ram Setu may be acceptable.
So you believe or not first respect others faith. Don't portray as you represent the whole Tamils.