Immunity Vs Defense.

Legion-5 shrugged. "I don't want to bully them. They are just kids. I am just taking a little from them to stay out of their way. But if they don't appreciate my kindness then they will regret it."

He truly thinks of them as kids and he thinks his extortion of them is a kindness. The rite of passage might be a competition to them, but it is not to him. It is a means to an end for him. To achieve that end, he extorted them. 

He didn't need to or had to do that. There are other ways to get points for him. But the other Supreme beasts need him to not try to get points by killing and eliminating them. So yes, he is doing them a favor by not attempting to kill them and just settling for extortion.