It was missing the accept header:
curl 'https://meta.discourse.org/post_action_users?id=507033&post_action_type_id=2' -H 'Accept: application/json'
It was missing the accept header:
curl 'https://meta.discourse.org/post_action_users?id=507033&post_action_type_id=2' -H 'Accept: application/json'