Why is "subpar" not "superpar"?

Dictionary.com defines par as:

an average, usual, or normal amount, degree, quality, condition, standard, or the like: above par; to feel below par.

In this case I don't believe that "subpar" actually derives from golf at all - "subpar" and the golf "par" both derive from the general definition of the word.

Though urban dictionary provides definition of subpar as 1) not measuring up to traditional standards of performance, value, or production. 2) below par in a hole, round, or game of golf, OED defines subpar simply as “used to describe something that is below average, or below what is expected,” as well as CED’s blunt definition, “below an average level,” period, no mention of golf.

The following examples I’ve picked up from newspapers and literature for my English vocabulary / usage collection purpose show even in sports, usage of subpar goes much beyond golf.

(1)A lower standard than customary or traditionally accepted norms, but not entirely unacceptable. For example, a computer's speed may be subpar, indicating that it is running slow relative to other computers, but this does not necessarily mean it is broken or unusable.

(2) It's exactly the kind of game the Washington Redskins have been mostly unable to win over the past dozen years. Nobody ran the ball with any authority. Donovan McNabb had, for him, a very sub-par passing night. But they did play defense and let the other guy make stupid mistakes.

(3) Cowboys signal caller, Tonny Romo had a sub-par free season, throwing one touch-down and two interceptions, and he was sacked five times.