Action, I wouldn't say that. I agree that metal is junk. I am also informed in the music community, and most metal bands have the "I'm going to mosh the crap out of that little 10 year old " style, but not all. Don't listen to Slipknot or Job for a Cowboy if you hate the screaming to the point where you can't understand it.
Some good bands from the metal genre are:
Hatebreed (not as hard as it sounds)
Metallica ( I personally don't like them, but they are ok)
Disturbed ( You can understand them perfectly)
I think part of our mis-aligned view on the subject is the fact that there are sooo many Sub-genres of Metal out there. Metal is the overall genre of music, which is normally defined as 2 or 3 distorted electric guitars, A LOT of drum work and energetic, or even harsh-sounding vocals. Metallica tends to be a little more mature about their metal, which is partly why they're able to reach a larger audience than many Metal bands.
What I meant by
Most North American metal seems to be written for more "hardcore" fans than us. We don't like our music to sound like junk, while some metal fans apparently do
is that it is very difficult to find a Good metal band in North America that a person who is relatively new to Metal music can enjoy. I remember really disliking metal until a friend of mine sent me a song by Nightwish. It was then that I learned that metal can actually sound good. I never would have learned that if I wouldn't have been exposed to "imported" metal music. As a result, I can distinctly hear a difference in sound from North American metal to European metal. In general, I feel that North American metal sounds more like a rock/punk fusion than what metal can really be. Even the band Disturbed, that you mentioned above, feels more like a punk band than the metal bands that I'm used to.
It is sometimes hard to define Metal from say, Hard Rock. This is why there are sub-genres of Metal, to help define this difference. All of these genres contain the basic elements of Metal/Rock, with differences. Metal music tends to have big-burly cymbal hits and crashes (hence the name, "metal") throughout.
Power Metal: High-energy, high-speed, Lots of drums, usually lots of guitars, and a vocal that can be either fast or slow, expressive or high-energy.
Examples:
Sonata Arctica - Don't Say a Word
Sonata Arctica - Don't Say a Word (this vid isn't very good, but it gets the point across. This song sounds much better on their CD)
Kamelot - Soul Society (a fusion of power metal and melodic/symphonic metal)
Kamelot - Centre of the UniverseAvantasia - Chalice of Agony
Symphonic Metal: Containing elements of a symphony orchestra fused with the essence of Metal music. It actually makes for a very interesting mix, in my mind.
Examples:
Nightwish - Beauty of the BeastNightwish - Ghost Love Score (give this one a chance to load. It's long, but amazing!)
Nightwish - Planet HellMelodic Metal: Mainly Rock with some enhanced effects and more action. Similar to Symphonic Metal but generally less complex orchestration. Many slower Metal songs fall in this category.
Examples:
Kamelot - AbandonedSonata Arctica - Last Drop FallsAvantasia - Sign of the Cross
Death Metal: The most aggressive, harsh-sounding form of metal that I know of. The vocals tend to be 'growled' to the listener. The rhythm and lead guitars control most of the song with powerful. This can be classified as the most aggressive form of Power Metal.
Examples:
Nightwish - The Pharoh Sails to Orion (fusion of death metal, power metal, and melodic metal)
Nightwish - Devil and the Deep Dark Ocean (fusion of power metal, death metal, and symphonic metal)
Goth Metal: A difficult genre to describe, but it seems to consist of elements of melodic metal, death metal, and anything else they want to throw into their music. I can't think of any examples off-hand. Goth metal tends to be a bit slower than their power metal counterparts.
(I am tempted to put Evanescence - Going Under (Goth/Tech/Melodic Metal) as an example, but I'll probably get that thrown back in my face, as Evanescence is not true metal. They're classed closer to rock/pop. Even so, I'm going to use this song as my example).
Noise Metal: Metal that is specifically designed to be LOUD. This music is built to throw the listener out of their seat. This is one of the least-organized-sounding styles of metal, normally referred to as chaotic. It is rarely used on its own (well, at least), as it creates a rather painful listening experience.
I can't think of any true examples, as I avoid this genre on purpose.
Tech Metal: A genre of metal that includes techno-like instruments as important elements or driving forces to their music.
Disturbed - The GameRammstein - EngelMany metal songs are fusions of the above, and other, genres. There are probably other subgenres which I can't think of right now. There is a lot of metal which actually contains clear elements of real music within it. Most of the songs listed above do not contain excessive screaming, and some of them are very clean, well-done pieces of music. Metal does have a place, the hard part is finding good metal in North America.

: I only mentioned a North American band (Disturbed and Evanescence) twice on this entire list.