This is the wonder of the unmerited favor of God and the reflection of His love and His justice coming together at the cross.
Unfortunately, many hear the message and turn away, thinking they are better than the mass murderer, so surely they will go to heaven. They will not.
Now, would He now look at those people and say to them, "well, I know I told you to believe, but I added a few extra requirements since we met last so it's more than just belief you need. Now it's _______ you need."
Does that make any sense that He would change the condition on how to gain Heaven??
If one reads the OT, you see it was about faith then as it is now.
Abraham believed God.
Gideon believed God.
Noah believed God.
David believed God.
and on, and on, and on.
The simple message of the Gospel is just that....simple. It's so simple it's confounded people. Some think....it can't be that easy. Yet it is.
You are correct sir.
My opinion is, Hell will be filled with "good people" who thought they were so good, that they went about trying to establish their own righteousness. Heaven, on the other hand, will be filled with "bad people" who were so bad, they recognized it, and fled to the savior for forgiveness.