That website isn't the official registry. The .coop TLD has been operated since 2002, with the official registry at https://identity.coop.

Neither the current authorized registrar list (https://identity.coop/register) nor the archived 2013 list (https://web.archive.org/web/20131019082806/http://www.nic.co...) includes register.coop. Where did you find this site?