Snarky comments aside, I hear this all the time, usually from people who have made no effort to try to answer the question for themselves and find out why ex Mormons might 'obsess' about the Mormon Church. How about trying a bit of simple empathy, before spouting such nonsense?
As someone who has left the Mormon Church, I think I understand well why. Here's just a couple of many possible reasons:
1. Having spent, make that devoted, decades of one's life to a religion only to find out later that it is not only false but that its leaders have used (in their opinion) questionable at best and highly deceptive at worst methods to hide aspects of Church history, or things that would have allowed them to make informed decisions, there can arise a great deal of bitterness at being deceived and profound sense of alienation. Many can't move immediately on from this and resume their lives, they need time to process and work through it. You really don't have any idea how difficult and traumatic this can be until you go through it yourself. Many understandably can't just 'move on' without a period of anger, bitterness, grief, etc. It can take time.
2. People seek out others for social support who share their experiences and views. Thus, the thriving ex-Mormon social media sites and networks. Particularly for those who are not accepted by their spouses, families, and friends after coming out, or who are judged, or condemned, or have their morality questioned, they can't turn to family and friends, so they go where they know people understand and don't judge (in theory). There they can talk about and again process their experience.
When I left the LDS Church, I spent some time at ex-Mormon social media sites, debated on discussion boards with LDS members, etc. I was angry, bitter, embarrassed, feeling like I wasted years of life on what I believe 'with ever fiber of my being' is a fraud. I honestly felt like I had wasted my life away. I wanted to talk about it. I wanted social support. I wanted friends who knew what I was going through. It took me about two years, and then I moved on. I have no interest anymore in any ex-Mormon sites, religion discussion boards, or even discussing Mormonism, except if people ask (inevitable since I'm from Utah). That said, I must deal with the Mormon Church every day, as my wife remains active, as do my family on both sides. That, and I live in a state dominated culturally and politically by the Mormon Church. As much as I would love to 'leave it alone,' it won't leave me alone, so I must deal with it still. I tend to do so mostly by ignoring it to the extent I can, but occasionally I am dragged back into it, like when I feel compelled to respond to ignorant posts, like this one.
