If they are tzadikim or not? is a good question. But worship is due to God alone. And the religious world is the opposite of worship of God. They worship dead tzadikim,-- all the rituals none withstanding.
Belief in God is rational. Everything has a cause. So unless there is a first cause, then you would have an infinite regress. And then nothing could exist. Therefore there must be a first cause. Therefore God, the first cause, exists. QED.