The things they could gain from the game were just too much to pass up. The chances of eternal life were just too tempting to waste time on protesting when they could be preparing for God's Domain. Besides, if they got eternal life, they would have a lot of time to protest in the future.
Of course there are others who didn't care that people could die and didn't bother to protest right from the start. AB is one such person. He is an outlier, but there are a lot of people who don't care for other reasons.
One of them is Black Knife. That is not his real name. It is a title given to him in the criminal underworld.
He was in jail when the game was beamed to everyone. No human was spared from the invitation no matter where they were, so he received one too.
This invitation was sent out to everyone, including children, handicapped people, and deathrow criminals. Anyone who could bear the pain of the game making a connection to their minds can join it.