Before Teddy Roosevelt's time, cowboys had a nasty reputation, thanks to Billy the Kid and other violent outlaws who ran roughshod over the frontier. Buffalo Bill's Wild West shows and late-19th century dime novels combined to recast the cowboy's image as an Anglo-Saxon hero and heir to the Arthurian Knights of the Round Table.
So let's look at the chronology the writer cites as historical cause and affect. First there was the age of Billy the Kid and other such outlaws who gave cowboys a 'nasty' reputation. Then came Buffalo Bill's Wild West Shows and the dime novels and they changed the cowboy's reputation by the time of Teddy Roosevelt.
The truth is, of course, the exact opposite of those statements. The first novels glamorizing the new breed of Westerner started at least in the 1840's - and Kit Carson was first lionized in 1849. Plus the dean of the dime novelists (a specific form that started in 1860) was Ned Buntline who started writing about the West no later than the 1860. By 1869 he had written his first book about Buffalo Bill. He later convinced Buffalo Bill to take to the stage in... 1872... and Buffalo Bill was touring the country by 1873 and did so for the next ten years performing Wild West stage shows. Then in 1883, he extended this brand by adding outdoor Wild West show extrvagandas.
Billy the Kid, however, was little known until his death in... 1881... and he only came to national fame after his killer - Pat Garrett - published his account of his life in 18882 - nine years after Buffalo Bill had started performing throughout the country and one year before he started his Wild West shows. And as for Roosevelt - he didn't become President until almost 30 years after Buffalo Bill first took to the stage.
Clearly - the time line the writer presents is... impossible. Now I assume the writer was taking this from materials provided by the Autry Museum, but even the most basic knowledge of American history should have alerted the writer and the editors that this cause and affect time line simply could not have happened. Particularly bizarre is the statement that before Roosevelt's time (and he came on the national stage only in the 1890's) - the American cowboy had a nasty reputation, since this was long after the Wild West Shows and the dime novels had captured the American imagination.
In fact, I'd really like to see any factual proof that there ever was any period in which the American cowboy had a 'nasty reputation. But, of course, facts are increasingly not what you are going to find in the LA Times.