You will have to ask those people for that answer. Each person is free to do as he/she pleases, and not all our decisions will be understood by others.
You're the one who says salvation comes according to our choices. It's a logical question to ask what determines those choices?
If you're not comfortable conjecturing about other men's "choices," then I'll ask you only about yourself. What allowed/caused you to "choose" Christ when others didn't/don't?