DaasYochid, if you’re referring to Feif Un, you have it wrong.
He was pretty much OTD while still in yeshiva. One of the Roshei Yeshiva wanted to expel him, but the highest RY there told the other one to let him stay, because after the year was over he’d want to leave anyway, and he wasn’t influencing anyone else – he kept things to himself.
If anything, it was in college (where I first met him), that he became more frum. He had some extremely bad experiences in yeshiva which made him not want to be frum. One of them was being told some of the same things I was told – that college guys can’t be frum. He asked the Rebbe if that meant his (Feif Un’s, not the Rebbe’s) parents weren’t frum, since they went to college, and he was punished for being chutzpadik.
Feif Un “dared” to ask the questions that yeshiva guys are not supposed to ask – he dared to ask “Why?” and he was ridiculed for it. For a religion that supposedly encourages questions, the right-wing yeshiva system is certainly doing a great job of doing the opposite. That was what drove Feif Un OTD. It started when he was in elementary school, and got worse over the years. In college, he realized that you can be a good Jew and not be sitting and learning all day, and decided to give it another try. That’s a big part of why Feif Un is so adamantly against chareidi Judaism – because he saw the hypocrisy in it, and their willingness to throw those who don’t fit into their system to the wayside.
In case you’re wondering, yes, I did check with Feif Un before posting this stuff about him, and he gave me the ok.