Why not?
Show me where Christ died for only some of our sins.
Who on earth claims otherwise.
However you seem to be claiming that God does not forgive all sins/sinners.
That means that grace is added to. That humans can actually prevent grace. How powerful do you think humans are compared to God? Not only can they corrupt His creation, they can overrule His taking back of it.
Richard
PS Jonah 4
11And should I not have concern for the great city of Nineveh, in which there are more than a hundred and twenty thousand people who cannot tell their right hand from their left—and also many animals?””
IOW innocent!