There is no reason why an agnostic cannot be as good or better a member of the Judeo-Christian community as any avowed true believer.
An athiest, not so very likely.
Atheists have a point of view to evangelize (as it were).
Agnostics, perhaps less so, perhaps they are willing to “coexist” as the popular motto puts it because after all, as far as their own standards are concerned, one of those religions they can’t believe in might be correct.