M.Ted - I don't see anything unusual about dorian mode tunes emphasising the minor chord and the major chord a tone below (E min and D maj in this case) - on the contrary, that particular pairing of implied chords is almost a cliché in Irish and Scottish music. (You get lots of A minor/G major tunes too, same thing)

That said - I fully agree with others that songs and tunes don't "have" chords - you harmonize them how you think fit - and I always grin when I see a posting asking for "the chords" to some song.

Anahata