"This source diff could not be displayed because it is too large" seems too limiting

In https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/30985/diffs, I have a diff that has this:

@oswaldo I don't think we should be hitting the 5000-line limits in https://docs.gitlab.com/ee/development/diffs.html#diff-collection-limits. Are we hitting some other limit? Why is the user not allowed to expand here?