- The Mormon church doctrine is that people who leave have fallen away, and are apostates
- Several messages from the central authority (called General Authorities) have disseminated over the last several decades telling congregants to shun apostates (soft), not listen to them (direct), and similar
- Wealthy parents have been encouraged by the central authority to not leave inheritance to their wayward children, and to use it to keep them adherent to Mormon orthopraxis
- Parents and congregants are often encouraged to be very bold in their attempts to keep wayward congregants adherent (until the congregants admits disbelief). "Ward Council" and similar organizing local leadership sessions are intended to share gossip to identify potential wayward congregants
- quitmormon.com is a pro bono service set up by a former Mormon in Utah and is the only service I've seen that is able to get records removed from the Mormon database records. If one does not remove their records, the central authority instructs local congregations to find people to keep their database records up to date.
These mix together and result in a large variety of experiences, often where the targeted wayward congregant is stripped of dignity and, eventually, respect in the eyes of people they spend substantial time with.
These issues are organization-wide and centrally driven, and hence the organization does not allow you to leave with dignity.
EDIT: I realized I made the "wealthy parent" comment across several comments. This is not connected to my experience, as I do not come from wealth whatsoever, but is something that has been observed in the past few years. I mention solely to point out the systemic issues I see.