That's a pretty good point that nobody here has raised yet
If there was a way to ensure basically that people didn't discriminate against people of their own broad religion who were of a different sect, and that such a law would automatically cover caste discrimination by people of upper caste background against people of lower caste background (whether or not either claim to profess any specific religion termed Hinduism), that would certainly be better.
There are a couple issues with this in practice, however, and this suffers even more strongly from the conceptual problem that discrimination between a Shia and Sunni or between a Catholic and Protestant, etc., is almost certainly already covered under religious discrimination, whereas caste apparently isn't.
A big part of the problem with this bill is that we actually don't seem to have a clear answer on the latter question--it seems like almost everyone is kind of just assuming that caste is or isn't already covered by existing law based on their preferences.
I'm not debating the literal law, I'm debating the effects of the law. Harsher sentencing for crack cocaine literally applied to everyone of all races. But... yeah, it was done that way to target Black offenders, sentencing them more harshly for a couple rocks than White stock brokers got for a kilo of powder.
Just because a law technically applies to all, doesn't mean it does so in practice.
This law does target Hindus. They may have a pervasive problem, but I'd prefer the solutions to be neutral to nationality or religion, like the ones we have now. Step up enforcement of existing laws so you can deal not only with caste-ism, but also sectarian strife among other groups. Shia or Sunni, Catholic or Protestant, Orthodox or Reformed, etc.