It does seem crazy that New York still has two man operation. A machine is also capable of confirming correct alignment to some marker, and won't get distracted or confused. I assume it's a union thing?

If you are going to spend millions of dollars (yes really) paying for an extra person on every train, clearly having them fixed in a place where they can point at a board so as to not automate an easy problem is a poor use compared to them roaming the train. Of course New York's trains still also don't have open gangways, so it wouldn't be easy to do that either. But a guard who actually strolls up and down the train helping passengers might actually make a useful difference compared to replacing a trivial mechanical sensor with a well-paid human.