I think that there is more to this question than has been discussed thus far. On the one hand, there is the clear differentiation between the relative uniformity of sports' pitches and golf courses. Other than the size of the hole and the treatment of defined areas under the Rules, there is nothing uniform and each course varies in the manner in which it tests a player's game. It was this lack of uniformity in the competitive test that animated the debates between Joshua Crane and others, most notably Max Behr, during the golden age. However, this position can be overstated. The course is meant to be a field of play. Designers and committees who emphasize beauty over playability often forget this central purpose as do "tree huggers", those who find "symbolism" in design etc. Thus while the course is not a uniform playing field, it is meant to be used for an athletic endeavor.
I also note many team sports are played on irregular fields in informal play. Basketball is played wherever a hoop can be hung. Football, either American style or what we Yanks call soccer, can be played on any open field as can baseball or cricket. So golf is a bit of a "tweener"