I think everyone's definition of heavy is different, or maybe certain people just have no idea. I may be one of those people as I've seen people describe Hageshisa to and even Different Sense as heavy. I agree with those people. I would certainly like to hear something you define as heavy just so I have a better idea of exactly what you're talking about.
I'm not an expert in the field of what makes something heavy or not, but from my understanding I believe it means that when you listen to the song if feels like it is actually crushing you with the strong atmosphere it delivers. Listening to that Boris song that was posted definitely made me feel that way.
What you are describing as heavy is music that is just either aggressive or angry. I think it all really comes down to the atmosphere. While listening to hageshisa to, I didn't get the same crushing feeling like I did with the Boris song.
