From the documentation:
This returns a list of releases, which does not include regular Git tags that have not been associated with a release. To get a list of Git tags, use the Repository Tags API.
GitHub’s UI is confusing, but this repository doesn’t actually have any releases, which are a GitHub-specific concept. The “releases” you are seeing are actually just regular Git tags.
Try this instead:
curl https://api.github.com/repos/JetBrains/intellij-community/tags