The backfire effect is real. If you call the church a cult and Joseph Smith a predator while talking with Mormons then don't be surprised if they cut you off and dig their heels deeper into Mormonism.

If you're sincerely trying to help a church member see things from your point of view, a gentle approach is critical. We all have psychological vulnerabilities, and when our core beliefs are directly attacked we tend to react emotionally, not logically.

I think more Mormons are helped out of the church by kind and sympathetic exmos than by exmos who constantly blurt out how culty and evil the church is. If anything, aggressive and mocking behavior fulfills the "teeth-gnashing exmo" stereotype and strengthens members' confirmation bias.

That said, I fully support whatever type of exmo you choose to be. The church IS a cult and Joseph Smith WAS a predator, so I don't judge anyone for pointing it out, even in front of pearl-clutching Mormons.