Hinduism Sanatana Dharma A Black Hole ?

These systems which decried the excessive rituals( Justifiably so) of Sanatana dharma ended up with Rituals.

They decried idol worship, landed in worshiping The Tirthankara, Mahavira and Buddha!

Yes, to an extent the statement that Hinduism is like a Black hole in the sense it sucks the best out of every system and assimilates it.

The reason is that while other religions were founded , had a founder and an intention to have followers.