Nonsense. If you're saying Witnesses do not believe that the New Covenant is for forgiveness of sins, you're wrong. And you miss the point of my post. Simply condemning Witness theology without refutation is a waste of time and a false path. That will not change a Witness' belief, especially if she is moderately informed. Within their explanations of New Covenant doctrine is I John 2:1-3, which says according to their Bible: "My little children, I am writing you these things that you may not commit a sin. And yet, if anyone does commit a sin, we have a helper with the Father, Jesus Christ, a righteous one. And he is a propitiatory sacrifice for our sins, yet not for ours only but also for the whole world’s. And by this we have the knowledge that we have come to know him, namely, if we continue observing his commandments."
They emphasize "our sins" in contrast to "the whole world's." Their belief is that the "our" addresses anointed Christians, and 'the whole world" everyone else, making or marking two groups. Good theology? Simply shrugging this off as wrong-headed theology is insufficient. Refute scripturally, or anything said in rejection is meaningless
In their favor here is the difference between a propitiatory sacrifice and a covenant. A propitiatory sacrifice is "peace making." A covenant is an agreement between carefully defined parties. An example is the Law Covenant made between the descendants of Jacob and God. Others benefited from it - the strangers in the land for instance - but were not parties to the covenant.
The issue here is: Is the New Covenant between a closely defined group within Christianity or does it encompass all Christians? Even if we thoroughly disagree with Witness doctrine here, we cannot say they limit forgiveness of sins only to the anointed. Clearly they do not.
There are other issues, of course. Sanctification, justification, new birth. But when considering between whom the New Covenant was made, those are a bit irrelevant. We fail if we limit our message to ranting condemnation and do not scripturally refute. Just saying, "Bad, bad, bad" is insufficient.