observanteen,
Speaking only from my personal experience as a BT, my neshama was pulling at me since I was a kid; however, misconceptions about Orthodoxy and Orthodox Jews was a huge barrier. I literally feared Orthodox Jews – I thought they looked down on me, considered me inferior, and wanted nothing to do with me.
It was a combination of finding resources and learning (finding authentically frum books is difficult if you are not frum! Non-frum sources have a lot printed on frumkeit, unfortunately) and small religious interactions with Orthodox Jews, culminating with approaching an Orthodox rabbi, that helped chip away the barrier for me.
So I agree with you, perhaps non-frum Jews don’t need a lecture, they don’t need to be told that they are losing their chelek in Olam Haba because they do X (when they honestly don’t know of X, even if told). What they need is a smile, a hand to guide them through a mitzvah and a hearty “Amein” to show them that the mitzvah meant something to Hashem and to Orthodox Jewry.