It's a good question that you pose, Landos, and from my observations of these young people and conversations with some, it seems there are several reasons they become interested. Some of the reasons are excellent, some not so good, but I think God can use many motivations to bring people home to the Orthodox Church.
I've observed a few young folks stuck in a time warp. They feel they just don't fit in. They're quirky. A few dress old school and want to feel attached to ancient history. They read about the Middle Ages and Constantinople and medievalism and the old days of yore, and they see the Divine Liturgy complete with "wisdom!" and "let us be attentive!" and "the doors! the doors!" with swinging censors and the smells and bells, and they feel like they're in a history book living it out. I suppose that is God's way of bringing them in, but they need to realize it's not the history channel, but a living, breathing faith and it all has profound meaning.
Some of them again don't feel like they fit in, so they are what some of us call "hyperdox." For the same reason papalists who were formerly Protestants become Roman Catholic sometimes, to look down on the "poor protestant rabble" and feel a sense of superiority not fitting in with the folks around them, some become Orthodox to call everyone a "heretic." I've actually had to deal with that lately. Some of these really young Millennials are obsessed with labels and calling everyone a "heretic." I find it off-putting and irritating. They all fancy themselves St. Athanasius or St. Maximus the Confessor fighting against guys like Arius or Nestorius. It's sometimes childish and actually damaging. I've actually seen this a lot.
Some are angry at their former life as a Baptist or Pentecostal or Anglican or Catholic, and now Orthodoxy gives them this feeling of "ugh, those poor pathetic _________'s." My dad used to call it the "reformed smoker" effect. The person smokes 35 years, quits, and instantly spends their days 24/7 mocking smokers as pathetic wretches.
Then there are the political converts. These folks see America from a conservative point of view. Nuclear family. I don't like gays. Dad is the head of the household and mom isn't. I hate abortion. I like my guns. I hate commies. They see Pope Francis and the current Catholic Church as liberation theology sell-outs and many protestants as too liberal, so Orthodoxy has that appeal. And within that group, sometimes I see these married folks and it has a pretty obvious "bake me a pie, woman!" tone to it and I've seen some of the guys trying to out-macho each other. It's odd to say the least. So they didn't find Orthodoxy because they love Orthodoxy, they found a church that fits what they already wanted.
Then there are the liberal socialists who like that Orthodoxy isn't as explicitly rigid with a catechism like Catholicism and they like the less harsh views of the atonement that we see in the West that are bloody and spooky legalism. But they bring baggage with them to Orthodoxy like "democratic socialism" and other youthful Marxist pie-in-the-sky tripe.
Then you have people who feel a spiritual calling and prayed about it. They read about Orthodoxy feeling unfulfilled but no ill will toward their former churches. They just want to serve God and be in the True Church, and through study and reading and perhaps from a friend, they find Orthodoxy.
Sometimes it's icons they see at a Greek or Serbian festival and their artistic interest is piqued and something stirs inside them to ask questions. The Holy Spirit pulls them in that way.
Sometimes it comes through a healthy search and conversation with a friend or someone they're taking a class with in college. They might see an OCF at their campus and find refuge there amidst all the LGBT brainwashing and all the legalize crack and bestality campus loons.
There are unhealthy reasons that some enter, wonderful reasons for others. Some stay, and I see some go. Some are immature on many levels, some come for the right reason.