From the article:
"A new study done at the University of California—San Francisco reports that people who regularly groom their pubic hair are 75% more likely to develop a sexually transmitted infection than non-groomers."
There is nothing there to put the 75% into perspective. Suppose that 4 un-groomed people in 1000 got an STD. If grooming increased the risk by 75%, that would mean that 7 groomed people in 1000 would bet an STD. The increased risk would not amount to much.
Now suppose that 4 un-groomed people in 10 got an STD. Then, if grooming increased the risk by 75%, then 7 groomed people out of 10 would get an STD. That would be a much more serious increased risk.