In the Hungarian minor scale we have the following intervals, expressed here in semitones, between the scale's notes (I to VIII):

I       II      III     IV      V       VI      VII     (I) / VIII
    2       1       3       1       1       3       1   

If we take the C note as the base, we have:

c       d       d#      f#      g       ab      b       c
    2       1       3       1       1       3       1   

If we take the trichord starting at position 4, [F♯, A♭, C], we have a chord consisting of a major second (F♯ to A♭: 2 semitones) and a major third (A♭ to C: 4 semitones).

I've been told that this major second is actually considered to be a diminished third. What is the reason for not calling it a major second? Why not accept this chord as the secundal-tertian hybrid it seems to be?