Speaking as a paying pax, I'm seeing two issues here, and the one that matters to me is not MCAS. I'm seeing that a commercial carrier put passengers on a plane that clearly had serious technical problems.
The fact that no-one involved knew about MCAS is irrelevant. The plane wasn't behaving normally or safely. Passengers should never have been allowed near it until it had been flight-assessed by qualified staff who get paid to take a risk. Why are Lion Air still flying?