I have played golf my whole life and continue to play today. Certain statements made here are just not true. A threesome always plays faster than a fivesome, wrong! Men always play faster than women, wrong! The speed with which someone plays golf is a direct function of how good/bad you are. In the fairway, no lost balls, out of the hazards, you play fast, if not you tend to be slower. However having said that I am a 8 handicap and play fairly quickly. With no one stopping us my foursome (similar abilities) can finish a round in a little over three hours. But from what I have read here these ladies were allowing groups to play through them (which is good golf ediquette) and were members of the club. That is what totally throws me, if this was a public course and they refused to step aside for others, or refused to follow rules that's one thing, but if these were members playing on a course they pay monthly dues for then this reaction was totally driven by something more than slow play. There is a underpinning of something going on that has not been reported. Workers at membership based clubs that I have been associated with would never treat a member this way. It could cost them their job.
I truly feel it was racially motivated based on the limited information, however I will say golf is a different sport. High handicappers should understand they are learning the game and since the USGA only recognizes a handicap up to 36 for men and 40 for women once you reach 3 over par for a hole you cannot record a score greater than a triple bogie you should probably just pick up at that point. My father never let me on a course till I was 13 and kept all my activity on the range and putting/chipping green till I could reasonably play on a course. In golf it is the individuals responsibility to know the rules and ediquette before ever stepping on the course and follow them at all times.