chalish, you are so wrong! Modern Orthodoxy does not have a pick and choose attitude.
I consider myself Modern Orthodox, and live in an area which is mostly Modern Orthodox.
My wife does not wear pants. She covers her hair. I wear a kippah on my head. So I don’t wear black and white all the time – so what? Do I need black and white to separate myself from non-Jews?
MO does not say pick and choose. Are there MO people who don’t keep certain things? Yes. However, ask any MO Rav, and he will tell you to keep them. No MO Rav will tell you it’s ok for a married woman to keep her hair uncovered. Do some do it anyway? Of course. That doesn’t mean MO endorses it. Plenty of so-called yeshivish people or chassidish people do things against halachah also. A chassidish guy once tried to grab my wife as she walked by him in a store (with me a few feet away, no less). Does that mean chassidus holds it’s ok for a man to touch a woman? Of course not! The same applies to MO.
You say the majority of the MO kids you know end up not frum. Well, where I live, the vast majority of them stay frum. Maybe some yeshivish people wouldn’t consider them frum, but most people I know do consider them frum. I know far more people who started out yeshivish or chassidish and ended up totally frei.
If you can show one thing which MO as a whole endorses which is against halachah, I’d appreciate it. I have a feeling you’re going to have a hard time producing one.