This is far from being "silly science." Historian and author Ted Steinberg, in his book "American Green: The Obsessive Quest for the Perfect Lawn" writes,
"It is estimated that there are roughly twenty-five to forty million acres of turn in the United States. Put all that grass together in your mind and you have an areas, at minimum, about the size of the state of Kentucky, though perhaps as large as Florida. Included in this total are fifty-eight million home lawns plus over sixteen thousand golf course facilities (with one or more courses each) and roughly seven hundred thousand athletic fields" (4).
Now, let's look at the numbers: 16,000 golf courses at 150 acres a piece (which I am using as a high average just to prove a point) is 2.4 million acres, or just under 10% of the total. Residential lawns and fields for football, baseball, etc., comprise the rest. Clearly, golf courses are NOT the issue here. Moreover, this other 90% is often maintained by individuals UN-trained in turf science or agriculture, the proto-typical "weekend warrior" who mows at too low a height, and slings fertilizer around like it's candy. All of this, at least when a petroleum-based fuel supply is assumed (as it seems like the UC Irvine study assumes), will ultimately lead to devastating environmental effects. Remember, the study is not saying that TURF is the problem, but rather the OVER MANAGEMENT of turf. So, even in my defense of golf courses, it is difficult to justify mowing fairways 2-4 times a week, or greens every day, or the various other heights of cut on a given golf course at such intervals, as these actions are done solely for the sake of creating "ideal" playing conditions to keep a business running; each time a mower is turned on, harmful gases are released into the atmosphere.
Really though, golf courses are just easily lumped in with the rest in the mind of the public, because whereas it is apparently difficult for individual homeowners to each be held responsible for their actions (which is minute for each particular lot, though the numbers above will show creates a far larger problem than the golf course industry), it is quite easy to blame golf courses and their relatively high intensity maintenance practices. It is perhaps unfair to group everything together, but maybe this just underscores the need for golf courses to answer the call to cut back their cultural practices and provide the public with a precedent to do the same (which many courses have already begun).