It doesn't say "PhDs", it says "Doctoral degrees", which may mean (it isn't clear), that EdD (Doctor of Education, a common degree for public school administrators), DBA (Doctor of Business Administration, usually from Harvard), EDB (Executive Doctor of Business, typically offered to already successful business people) and other similar specialized but not necessarily "professional" degrees (which I interpret to mean MD, JD, DDS, chiropractic, etc.) would be in this group.