Well, yes, the operatingsystem fact is OracleLinux.  Perhaps I've confused this matching logic in other modules and it just works by chance.  

Confer with:
https://github.com/example42/puppet-java/blob/master/manifests/install.pp#L70
https://github.com/example42/puppet-snmpd/blob/master/manifests/params.pp#L28
https://github.com/example42/puppi/blob/master/manifests/params.pp#L46

and others which I have not contributed to.  I thought the point of the /(?i:pattern1|pattern2|pattern3)/ code was to match patterns not enumerate actual Operating System Names.  Am I not understanding this correctly?