One of the interesting thing about people that go "off the derech" is that they go all the way off, slamming the door behind them as they leave. The living room sucked so they walk through it, the kitchen and the entrance hallway, muttering in the rage as they walk out the front door.
An obvious question is: why don't they consider Modern Orthodoxy? Why is it all-or-nothing for them?
Well, the answers you get are pretty repetitive but they're also interesting for the contradictory attitudes OTD's seem to have towards Torah observance.
The first is that the religion is all bovine excrement. Dig a little deeper though and specific complaints come out. The world isn't 5769 years old. The history of the universe contradicts a literal reading of Bereshis. There's no archeological evidence for almost anything in the Bible, especially Torah miSinai. There's no proof for the existence of God. The laws don't make sense. The texts are corrupted and changed over time. They're outdated. It's all about the chumros. There's a disdain for secular education. They hate women.
Then, having made their choice they mentally go one step further - from "I've got a problem with these things" they quickly move to "I've got a problem with these things and there's no solution".
This is perhaps why Modern Orthodoxy has never been appealing to the OTD crowd. For one thing, there's this strange dichotomy that gets set up in their minds. To wit: the only legitimate form of Judaism is Chareidi Judaism with all the problems they have with it. Anything else that differs is a fake form of Orthodox Judaism and therefore beneath their notice. Quote from Rav Eliashiv and you'll get a vitriolic emotional response. Quote from Rav Willig and you'll get "Oh, that's just Modern Orthodox crap".
It's like saying: I hate Coke, therefore I hate all colas and I'm not going to try Pepsi or Royal Crown because only Coke is the real thing.
Imagine the threat that Modern Orthodoxy poses. A legitimate attempt to reconcile Bereshis with natural history is permitted and encouraged. There is actually archeological evidence for the Bible. There are firm philosophical proofs for the existence of God. The laws do make sense when interpreted properly. There's no need to believe the Torah has not changed one single letter since Moshe Rabeinu, a"h, received it. The halacha is dynamic and addresses modern issues. You can go to university, in fact that's a plus. Women play an important role in the family and community life.
It's no wonder that the OTD/skeptic crowd puts as much effort into delegitimizing Modern Orthodoxy as the Chareidim do. The middle ground is always a threat to the two extremes.