OutputDefault is being applied to ANY ES output, rather than only apply to our default ES offering.  There is a similar functionality available for a defined instance of an Elasticsearch output, but the defaults should not "merge" into the customer defined instance. 

The documentation needs to be updated to correct this as well:  
https://issues.redhat.com/browse/RHDEVDOCS-4549

Notes:

https://github.com/openshift/cluster-logging-operator/pull/1668
https://github.com/openshift/cluster-logging-operator/blob/master/internal/k8shandler/forwarding.go#L41