I think any religious scripture that hands down Divine Laws in every sphere of life is specially vulnerable to modern science and education.

For the Hindus, the only truly divine scripture comparable to the Koran/Bible, straight from god's mouth are the Vedas and Geeta.
Vedas are a combination hymnbook, magic formulas, a few speculations about the origin of universe and some historical material. You cannot attack it the way you can attack God's order to slaughter Israel's enemies or stoning people to death.
Gita is simply too mystical to give you a good debate on social grounds.

the rest of the shastras, including the lawbooks, are revered but hindus feel free to ignore or modify them.

I think this is one of the reasons why criticisms against hindu holy books had never been so virulent as those against the bible/koran.
The rest