I've always felt that a minor scale should be [in C]
C D Eb F G Ab Bb C and the same back the other way.
That's what I would call a minor scale, but the standard harmonic and melodic don't do that.
With notation programs such as Finale, it's easy to notate music any way you want. I've sometimes omitted a key signature when I felt it was better not to have one. Some early classical pieces, and others I imagine, you can't really say what key they're in.
I've also seen pieces in G minor notated with only Bb in the key signature. I feel that's a bit confusing as we're used to seeing the 2 flats.
In the original post it's stated that minor scale key signatures are wrong.
If I was notating a harmonic or melodic minor scale just for the tune, I think I might not use a key signature. Depends who it was for.