I used to be semi MO
I left for two reasons
(1) Difficulty in finding a shul or community that really lived up to some of the MO ideals I was looking for. Not saying they don’t exist. Just saying that I couldn’t find them in my area.
(2)They were on the wrong side of the Slifkin issue.
I’m not even debating the actual issue itself It is just that the incredible Emunah Peshuta towards what scientists say and the quick and easy dismissiveness towards what LeHavdil Chazal said, which is very prevalent in many segments of the MO, seems to be a major factor in their lack of ability to keep an enthusiasm for Torah. In my case it caused me to leave,