I believe the core component of faith in the Lord, Jesus Christ, is holding onto the belief that all people are redeemable - and, even more importantly, that all are worthy of redemption and that each needs it just as badly as any other. Some examples of people who appear to be irredeemable might be more obvious than others, but they are exactly the same in the end - since "all have sinned and come short of the glory of God".
me, that is the heart of faith in the Lord, Jesus Christ - faith in what
we believe he did and/or symbolized through his life and death. Any
time we write off someone as irredeemable, we write off the atonement in
a very real way and "deny the faith" in practical terms.
We, of all people, ought not condemn or give up on others - given how badly we want God not to condemn or give up on us.