Jeremy-- "Still exist"
The fact is that a single standard never existed, despite attempts by the associations to develope and implement a single standard--
From the "History of Course Rating"-- "The first measure of course difficulty was par. That developed from the concept of what would be the score for perfect play at Preswick, site of the Open in 1870?. Each course then developed its own "opinion" of par.
However, the first course rating system was developed by the Ladies Golf Union starting in 1893(in the British Isles) which was designed to develope seperate handicaps for women--as stated "by 1900 the LGU had done what the men had signally failed to do--establish a system of handicapping that was reasonably reliable from club to club."--
The Ladies then started, both in the Isles and in the US, to assign a "Ladies Par" based on Ladies play, which would compute their handicaps--
In 1911 the USGA, in an attempt to catch up on the mens side suggested a "par rating" for each course "based on the play of the US Amatuer Champion, Jerome Travers"--However on the mens side each course was permitted to establish its own "par rating"--
Both mens and womens associations functioned in tandem, but seperately with course ratings being established from the mens side by the standard of the US Am Champ and the ladies by the US Womens champ--
It is interesting to note that the US AM is not restricted to men. Anyone, children, seniors, ladies, midams, aliens, men/women from Mars may compete in the US Am, and the "model scratch golfer" is created from the average qualifier in that event-- When the slope system was conceived the "bogey" golfer was also necessary--and so, as you may know that golfer who would generally shoot 18 strokes higher than the scratch golfer on the average US course(fixed at a 113 slope) was charted--again there was no gender limitation on that "bogey" golfer-- He/she could be a child, women, senior, alien, etc--the only criteria was to chart the game of that player who would shoot, on the average, 18 strokes higher than a scratch golfer on that "average"(113 slope) course--
It was not the USGA, rather it was the women on the committee, representing the ladies side, who insisted that the seperate ladies slope and bogey golfer be maintained(rejecting the suggestion that the game of the best golfers, be they women or men, seniors or children, become the model scratch and the game of those shooting bogey golf, be they men, women, children, etc; be used for all golfers)--
Rather the women insisted that a seperate system be used for women only, based on the best of the women(the US Womens Am which includes only those female at birth) as compared with the "bogey" lady(that lady who will score 18 strokes higher, on the average, over the lady scratch)--
I am sorry that the historical facts don't fit your notion of "sexist" or discrimination, but they don't--
If the ladies, who are eligible for the US AM, MidAm, Sr Am, US Open championships, demand that championships be held for ladies only is the USGA(and the R&A) being politically incorrect in honoring that request?
If the women, who for over 100 years, have insisted that handicaps be computed and based on courses they set up for women and using the "par" standard for just ladies(and not all golfers), is the USGA and R&A being "sexist" and politically incorrect in honoring that request--
If you so contend you have lost me entirely!