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all a scale is, is a series of notes, yes? and a note, in and of itself, is can not be described as being melodic, yes? it is only melodic if you use it in the context of creating a melodic arrangement. the melodic minor scale is a gathering of notes, yes? as we can see, the notes themselves are not melodic. it is called a melodic minor scale because those particular groupings of notes, in that arrangement, tend to be useful in creating melodic arrangements. however, one is capable of using a melodic minor scale to write music that is not particularly melodic. while the harmonic minor is more common in black metal, both brutal death and raw black metal bands have been known to utilize the melodic minor scale in the creation of pieces that were not particularly melodic. after all, all the scale is is a series of notes. this series of notes can be supplemented with other notes from compatible scales and modes. they can be supplemented with chromatic runs. they can also be supplemented with notes from incompatible scales and modes to add "evil" sounding dissonance/atonality. and, interestingly enough, both the melodic and harmonic minor scales include the tritone, which is a particularly dissonant combination of notes, especially useful for creating the types of sounds sought in raw black metal and brutal death metal.

in fact, in the right context, you could use any scale to make raw or brutal music, even a major scale, provided you use it properly (to provide dissonance with a non-6th minor scale, for example).

so you acknowledge that the melodic scale CAN be used to create non-melodic sounds. that's all i was trying to point out.