The abstract states that type 1 HSV causes oral sores and type 2 causes genital sores. This is incorrect - it is now well known that either virus can manifest in either location.
There is a "home ground advantage", though - HSV1 infections on the genitals tends to have fewer outbreaks and they tend to be of lower severity. Same for oral HSV2.
Edit: to add to this, I think it makes the research far more significant to a lot of people - for some, it is just a facial sore that is a bit painful and embarassing. For others, it is an incurable sexually transmitted disease that can result in anxiety, depression and even suicide. There is still a huge stigma associated with genital HSV (either type), even though as much as two thirds of the world under the age of 50 are infected with type 1 alone.