A number of good points have been brought up on this thread that say we should go ahead and take the Gospel to these people. The main idea seems to be to do it gently.
The only points where I think we diverge are due to a difference of opinion or possibly an incomplete understanding of two concepts:
One: We appear to disagree on whether or not it is ‘necessary’ to bring Christ to those who already live ‘moral lives’ without ever having heard the word of God. The society that in its actions, constitutions, etc. seems to understand the ‘law written on our hearts’ yet lacks knowledge of Christ may be ‘proto-Christian’ to me, ‘Christian-in-all-but-name’ to you–yes? I, with others, think that being a Christian in the Catholic tradition is more than just ‘doing Christian things’
if one does not know Christ. After all, Buddhists, animists, pagans, atheists, etc. can be and are capable of living in a very Christian way yet do not ‘know’ Christ or His teaching. While as you say a ‘gentle’ (more on that later, that is the second point of disagreement) treatment is necessary that respects the people as people and not ‘tabula rasa’, I don’t think that you would say that we ‘need not’ bring the gospel to people who already live good moral lives. Otherwise. . .the crux of the matter --why does Scripture (and Tradition) say that we must preach the gospel to all? Not, “preach the gospel to the ones who seem to need it --leave the kind-hearted gentle pagans etc. alone, they’re already following Me.”
Second: “Gentle” preaching. Again, this depends very much on individual POV. To you, gentle might mean spending years–generations–living with these people without ever saying a word about Christ, just ‘modeling’ Christian behavior and hoping that someday the Spirit will ‘lead them’ to ask, “Say, you seem to be living a good life that has ‘more’ than I know. Can you tell me what has made you this way?” Or it might mean starting out with just speaking out to one or two people about “this wonderful person” and giving examples of parables, and then waiting for people to ask for more. Or sadly, there might be some with the attitude of “you ignorant heathen, living without God. . .accept JESUS as your savior or burn in hell. . .” Now my opinion here is that of the 3 examples, the first is an extremely passive one, the second is a reasonable example of true gentleness, and the third an example of extreme aggression. If you find 2 to be a good approximation of what you find ‘gentle’–well, then we agree. If you think 1 is best–we disagree. I’m sure you’ll find 3 totally unacceptable (I do too) --but probably fear that people are going to act that way. If that’s what you fear, and that is what is leading you to insist on the gentle (and I mean, the gentleness of #2)–again, we agree.
So you see, there is a very broad notion of what ‘gentle’ and ‘respectful’ can be out there. I’m all for gentle and loving, but not to the point that I would either try to downplay Christianity as ‘this is the way I worship, it works for me’ (because it isn’t ‘just for me’), or be so respectful that I conclude "gee, you people are already doing fine, you don’t need to hear about Jesus Himself as you obviously already know all you need just living the way you do.’
I would be honest that I truly believe in the truth of Catholicism and how important it is, since there is such a truth, for everyone–not just me–to know and hopefully to accept yet–yet I would be most complimentary of how wonderful these people are already and would be sure to acknowledge that.
Will there be problems when the gospel is spread? Possibly. Does the possibility then free us from the need to preach it? No. Be gentle --but firm for the right; loving–loving enough to risk offense and worse for the sake of Jesus; and trust in God. He wants everybody to know Him – All of Him.