Here is how they can say:
they do not believe that they are the only believers who can win salvation.
Do they believe that they are the only ones who will be saved?
No. Millions that have lived in centuries past and who were not
Jehovah's Witnesses will come back in a resurrection and have an
opportunity for life. Many now living may yet take a stand for truth
and righteousness before the "great tribulation," and they will gain
salvation. Moreover, Jesus said that we should not be judging one
another. We look at the outward appearance; God looks at the heart.
He sees accurately and judges mercifully. He has committed judgment
into Jesus' hands, not ours.—Matthew 7:1-5; 24:21; 25:31.
I'm not sure where this is from, probably from one of the questions from a reader.
pseudo