When Barack Obama was running for President, one of the things America found most mesmerizing and admirable in his campaign was how the youth got involved and how they really cared. They went out, near and far, knocking on Americans' doors, speaking to pedestrians, inviting them neighbors to rallies, asking them to sign up to vote for Obama. 'Wow!', the world exclaimed, 'These people really care about something! Isn't that incredible?!' And these Americans responded - Obama won; the youth had made a difference.Now if you suggest to someone to invite their neighbors/co-workers/classmates to a Shabbat dinner, or ask if they want to find out more about Judaism... People will jump at your throat like you're from Mars - 'What?! Are you crazy?! Do I look like a nut-job proselytizer? That's invasion of their privacy! People would never respond to that!' (from R' Dan Smokler)
On another note, there is a certain project that entails college students running Pesach Seders for Jews in Ukraine and the FSU - a very worthwhile and popular endeavor (see here, here, here, etc.). But what often goes unnoticed are the hundreds of spiritually and religiously starving Jews just around the corner from these very students' homes and schools. Sure it's cooler and crazier, more exotic and more exciting, but is it that much more impacting? Imagine American Jewish college students leading Seders not for elderly Russian Jews but for... American Jewish college students! They'll even speak the same language! Imagine the connections that could be forged, the meaningful conversations that could be had, and the ease there would be in relating to one another! (see for yourself here)
I think the issue common to both scenarios is people's fear of dealing with things that are too close to them. Often it is easier for people to talk about some rote debate on politics than about to Whom we pray every day. Maybe people are more self-conscious about their religion, and more afraid of dealing with it and truly facing these issues themselves (not that any encounter with a non-religious Jews will necessarily bring to light all of one's worst religious fears, but it could). Also, it's easier to talk with someone who, merely due to their language and culture is at a distance from you, then with a peer, for whom lack of communication cannot be blamed on language barriers. It is comforting having a barrier between you and the 'other', between you and what really matters to you, as opposed to having a real "heart to heart", which takes a lot of comfort and courage.
Sharing something close to you with someone close to you, who is different than you: more difficult- yes, but more rewarding and impacting - definitely.