All the animal sacrifice accounts in the Bible have always made me uncomfortable. I do not think I ever bought into the idea that this was instructed by God. I kind of always knew this was just screwed up humans doing screwed up things in the name of God as has always been done.
Seeing the Hindu slaughter is sickening. Not so much because all those animals died (as was mentioned, hundreds of millions/billions of animals are slaughtered every year around the world for meat consumption), but because of the brutality of it and the lack of compassion for a humane slaughter. The wastefulness. The bloodlust.
Industrial animal farming is also very brutal. They treat animals as protein blobs and their lives are miserable. It does not have to be this way. There are ways to raise and slaughter animals that are very humane. I am very familiar with these types of humane practices.
Back to the OP, yes, the similarities between the animal sacrifices of the OT and the brutal Hindu carnage cannot be ignored. It is reprehensible.
Let us not forget, we are all *supposed to be* worshipping a God that instructed Abraham to sacrifice his son, which he was willing to do. I, for one, never ever believed that story in the Bible. I think it is bullshit and no loving God would ever test "His friend" like that. Just another wacked out story in the Bible.