Guys, calm down. When Kerry signed up for the Navy, he
enlisted. Then he went to training and Officer Candidate School. When, in 1966 (the year this document is dated), he graduated from OCS, Kerry was
discharged as an enlisted man, hence the DD-214, so that he could
accept a commission as an officer.
Every officer who's been in ROTC, or gone through OCS, has a DD-214 just like this.