Found the Solution:

TLDR: Pipe your struct into a changeset first haha

Incorrect:
post |> Api.Org.Repo.delete()

Correct:
post |> Api.Assets.Post.changeset(%{}) |> Api.Org.Repo.delete()

Screenshot 2022-01-20 at 9.38.14 PM1170×408 26 KB

Explanation
Ecto’s constraints_to_errors function uses the changeset to detect the constraints, however because I piped my struct directly into the Repo.delete function instead of passing it to a changeset first, the constraint I set was never picked up

Screenshot From Ecto:

Screenshot 2022-01-20 at 9.23.46 PM1200×319 24.1 KB

Glad you sorted it out!

As a minor note, copying and pasting text works a lot better than screen shots. It allows others who want to help to copy some part of your text and edit it easily to improve it without having to retype all of it by hand. It also works better on different resolution / size screens.