It's always the term "disgruntled" that is used when attempting to discount the experiences related by people who left an organization. What exactly does "disgruntled" mean to you? Take me, for example. I've spent decades of my life as a true believing member of the organization, willingly giving an incredibly significant amount of income, time, and work toward it. And then I discover on my own decades later that I had been indoctrinated to believe in a lot of false stories. This discovery was a very slow process that involved a lot of time, energy, and research. The psychological toll of reframing your entire worldview is large. I benefited a lot from online communities where a lot of people were going through the same journey. I'll always be a person shaped by my previous decades of experience as an active believing Mormon. Did any church members personally treat me badly? No. I've always fit all the right demographics, had the right behavior, and am the correct sexual orientation. Outside of being quizzed and shamed for masturbation as a child, I generally had it pretty good in the church, and I loved it. Did any church members treat me badly after leaving the church? No. They've been respectful enough about it, and I've had some good conversations with some of them.
And yet people like you constantly come along and want to categorize me as simply a "disgruntled exmember" with no opinion worth listening to, for the mere fact that I still participate in conversations about it online and in person with people who have had similar experiences as mine. This is a perfect characterization and example of what people who leave the church have to deal with. Even I, who never had it badly in the church, and was able to leave without too much drama from the local ward, will be labeled as an untrustworthy disgruntled apostate the moment I try to give a different perspective on this organization I was heavily invested in for decades. Online communities like /r/exmormon have a very large portion of people like me who have not had bad experiences in the church or leaving the church, but yet still have plenty to talk about for what should be obvious reasons.
And who are the people whose opinions we should trust about the Mormon church? Why obviously the believing Mormons of course. Trust the people who have been taught and trained consistently their entire lives to be "member missionaries" and put the best possible spin on their church to outsiders. They're not disgruntled, so therefore their opinion matters more. Trust the used car dealer to make the most honest assessment of the car they're selling.