I recently read about a couple that went OTD. First the husband, who had learned in kollel, came to the conclusion based on purely intellectual reasons that he shouldn't be religious. Then the wife did her own independent research and came to the same conclusion [it had NOTHING to do with her husband's decision๐. Just a former Bais Yaakov girl who can't read classic, basic Jewish texts such as Gemara in the original, who thinks she disproved the veracity of our 5000 year history and traditions]. So off they went to a life of Nothingness where all that exists is the body and material needs... How utterly sad and tragic.
So it is important to establish a fact. It is "Fake News". There is no such thing as doing ANYTHING for purely intellectual reasons. This is not merely an insight of the Torah and Chazal [for those for whom this is not enough] but modern research has proven this quite conclusively. See for example the [utterly fascinating] writings of Daniel Kahaneman, Dan Ariely and Jonathan Haidt [all Jewish coincidentally ... or not coincidentally. And all completely secular] who are at the top of their fields and numerous other scholars and researchers.
People are not irreligious for purely intellectual reasons nor are people religious for purely intellectual reasons. There are much stronger forces at work than pure cognitive deduction. We purchase or don't purchase an item, marry this person or that person, choose to live in this place or that place etc. etc. for many reasons and due to numerous factors that are almost always hidden from the very people making these decisions.
There are questions on religion. There are also question on not having religion [like - how do you explain EVERYTHING? "Nothing" created everything? Big kashya...]. Questions are not a reason to reject Hashem and the Jewish people and a heritage for which our people have willingly died for from time immemorial.
The upshot from this is that when we raise our children we have to make sure that being religious and keeping mitzvos is a pleasurable experience and that their relationships with spiritual figures [and primarily their parents!] are positive. It is hard to leave something that makes one feel so happy and fulfilled.
To be clear. I believe [as do all faithful Jews] that the Torah is true, regardless of anyone's personal experiences or choices. But the reality of Hashem, the truth of the Torah and the existence of the world to come is not enough to keep people on the straight and narrow. They need to like/love it.
A religious Jew believes intellectually that learning Torah is a big mitzva and that he will be eternally rewarded. But that doesn't stop all of us from wasting time... The best way not to waste time is to love learning and doing mitzvos. Then even the yetzer hara won't be able to get you to stop [he might get you in more subtle ways, though...].