It doesn't matter if you are a muslim, christian or hindu. All indians are raised to place reverential respect for parents, family, honour etc.
the same as many cultures.
It is drilled into heads from an early age to never disappoint parents,
which is wrong on their part.
they sacrifice so much for you,
again, wrong on their part. if they had such a crappy situation that they "needed" to sacrifice for you, then they shouldn't have brought you to this world by giving you birth. let's remember who chose for you to be born. it wasn't *you*. it was your parents.
they know what's best for you and so on.
which is false.
So naturally, when you reject your parent's religion, it is viewed as rejecting your parents. Hence the guilt.
The feeling of guilt would only happen if you *agree* with those ideas. Just because these ideas were pushed on you doesn't mean that you live your life by them. And for the people that did live their lives by this crap, fortunately they have the ability to rid of themselves of it.
Even if you know "logically" there is no actual wrong, your apostasy will cause them pain and shame.
Not your fault. That's *their* fault.
And when religious parents sacrifice a lot of savings to help you study abroad, it's a double dose of guilt, because you are "using" them for their money,
Bullshit. The parents brought him to this world. It's their responsibility to help their children become independent adults. And this is their responsibility regardless of whether or not the child decides to believe certain things, like religion.
but still rejecting their faith and also pretending to be devout.
So what? If they feel bad, it's *their* fault for doing so. They should change their minds. They are being stubborn.
Guilt is normal and a natural outcome of such an upbringing. It's not a healthy outlook, but it means you have an conscience. Over time, the guilt will subside. It is part of the healing process.
Time doesn't fix it. Some people live and die never fixing the guilt. Why? Because they never actually change their minds on the subject. They continue believing that they are guilty. They continue holding on to the guilt trip of altruism, even though they've gotten rid of the wrapper (religion).
What fixes it is changing your mind.