For what it's worth, I loved every minute of my EFY sessions!
I attended an express session in Anchorage '04 and a full-out session in Calgary '05.
Being surrounded by cute girls for a week was worth it in every sense imaginable, considering that I believed it all at the time. Yes, it involves heavy indoctrination, but hey, I had fun and that's what counts.
By the way, before my '05 attendance, I was not really looking forward to a mission (I turned 18 at the end of '05), but going home I was 100% dedicated to going. Hell, I even managed to not do "the big M" for two weeks following, not to mention once while there - that's three weeks! hah! The spiritual high lasted about a month and a half, and I never went on a mission (thank TFSM).
Something special goes on at EFY. Also young adult conferences, bible camp, trek, temple dedications...
You can whip young people up into an emotional frenzy, then tell them this frenzy makes them special because they can feel the spirit.
It is a psychological phenomena that only works in groups. It conditions the young people think that they have had an undeniable spiritual manifestation, making it less probable they will abandon the faith later on.
Not to mention the number of families I knew who dropped a "troubled" child off, often without telling them where they were going, so that EFY could "fix" them.
Maybe my childhood ward was a standout of handsy teens but the back seat of whatever vehicle you were in saw more petting than a zoo on the way home from stuff like EFY.
I think they should have called it Especially for (Horny) Youth.
It's where I got my testimonkey of jeezus. You know the deal -- play "I heard him come" by afterglow, show the kids a slide show of jeezus picking flowers with little kiddos, have kids tearfully bare their testimonkey. Brainwashing of the highest quality.
Ironically, it was one of those LDS youth camps that caused my niece to resign. She told me that they had all the kids stand up and proclaim their individuality in unison, repeating by rote the same words! She was aware of George Orwell's writings and, of course, deeply disturbed by the exercise.