When athletes sign a contract, they know what is expected of them.
If you're going to write something like this, wouldn't you at least find out what the contract actually says first?
But lack of research notwithstanding, I agree with Transmo. It's sad that this is rehashed year after year.
I would say that the reason is 2-fold:
1. Whoever brought this up has Green on his team and is upset at missing game(s).
2. The perceived inconsistencies in his taking time off for Yom Kippur.
Keep in mind that I understand the magnitude of this day in the Jewish religion. I am merely pointing out that if it is truly important to him, he would take this day each year.