HeavenDuff, thanks for sharing your point of view.

This is not what I meant, but when it comes to "softer and lighter" albums (both metal and non-metal), I think it works for me this way too.
Hmm.., I think it works for me in a similar way when I listen to a Japanese post-rock/math rock band toe (their albums have a mix of ''technical'' drumming and melodic guitar playing): their music is pretty enjoyable, and I also admire the musicians who created and mixed the complexity of the uncommon time signatures, the intensity of the drums and the beauty of the guitar melodies.
But for me it is significantly different when it comes to extreme metal albums because all these components/characteristics that make an album less accessible (such as not catchy/non-melodic metal music, complex/chaotic song structures, odd time signatures, extremely fast/slow guitar and drum playing, some too strange and atypical sound(s) of electric guitars/drums, dissonant metal music, adding harsher/darker non-metal elements (from more extreme kinds of electronic music/samples), weird electro-distorted vocals/voice samples, too 'inhuman' harsh vocals, non-melodic singing, etc.) tend to feel much more intense on these albums. All these components/characteristics not only make an extreme metal album more challenging ''technically"/mentally but also they make an album more uneasy listening physically and emotionally, and this is especially noticeable and difficult for me when it comes to extreme metal albums that have more aggressive/unsettling mood and atmosphere.
I'm sorry, I don't know how to explain this more clearly (and I think it's subjectively anyway).
Yes, I'm more of a fan of melodic music (both metal and non-metal) and simpler song structures, but this is not only because this music is more easy to listen to but also because it tends to sound and feel more "peaceful" and "safe" than non-melodic/chaotic music. Of course, there are some "creepy/horror/nervous" kinds of melodic music that can make a song/album even more unsettling, so it doesn't always work that way. But when there are some melodic songs/parts/elements on an extreme metal album that (remotely) resemble "soothing sadness/beauty'' kinds of melodies, there are more chances for me to get into this album. Maybe this is a little irrational but this is how it works for me.
But I also need to say that (relative) melodicism of music/singing and simpler/more common structures are only parts of what the description "moderately extreme" is for me, because there are also lyrics/imagery/general mood of an album that can also be "as extreme and unacceptable as possible", and in most cases I am not able to separate the music from the ''way too extreme'' lyrics/imagery.
The album "Human Antithesis" by Void of Silence that I voted for in this poll is one of my all-time favorite "moderately extreme" metal albums because I like the music (both the sound of the music and the songwriting are impressive and interesting for me) and the vocal performance on the album (and the lyrics on the album-titled song are one of my all-time favorites), and also because it is one of the very few "martial industrial-inspired" metal albums I was able to get into (both musically and lyrically).
But it's also understandable to me why fans of more extreme metal music prefer some other "martial industrial-inspired" metal albums that sound much more intense and harsh.