The Ajivikas were right
I think that The Ajivikas were right in their philosophical position.
Modern day science might agree with their hard deterministic stance.
As far as we know up until now, the brain is not truly independent in its approach to make choices and it takes the decision before we even get consciously aware of that decision.
Whatever we do, it's all dependent on multiple factors, majority of which are not in our control, like our upbringing, our family, our genetics, our environment, our education, our place of birth, our culture, our exposure to the said environments and ideas etc.
We can't say that free will exists because humans are not truly free in their ability to make a choice.
Every choice is bound by a long chain of actions going far back and everything we do or think can be traced back to this chain.
Ajivikas used to say that there is no free will and everything is determined by fate or Niyati, just like a ball of string will only unfold and open up as much as the length of the string allows it.
Their fatalistic position might be even seen in a negative light, even in their times.
For example, when even The Buddha used to get angry at the mention of Makkhali Gosala, who was the major teacher of this philosophy of Ajivikas.
And it might be seen negatively even in this age.
But from whatever we know until now, their position might have been the correct one.
So all in all, I think that the Ajivikas were right to call human lives and the world as fatalistic or hard deterministic.