Gardiner addressed a historical point regardless of genre. His hypothesis was strengthened by noting marching tunes that were based on the time taken to travel between known barracks, instruments not used due to physical limitations at faster tempos and how sub melodies in many genres require certain tempos in order to “work.”

Please try to see beyond his label and note, not necessarily agree but note his interpretation of historical style.

If you require people to use the term “medieval” in order to accept that a large body of academia believe tempos were generally faster in use from medieval to c18 time, then I suggest you at least research it rather than embarrass yourself repeatedly.