Yes, obviously there's a spectrum between those points. That's not what I'm talking about though. I'm talking about the consequences of being unforgivable, no matter where the line is. If something is unforgivable, you're setting a line in the sand beyond which a person has no reason or incentive to not continue behaving in that way because it doesn't matter, they're going to continue being punished.
No it isn't, there is a whole spectrum between "forgiving everything" and "forgiving nothing".