I'm calling them horribel musicians because they're horrible musicians, it's a fact. I'm calling them retarRAB not because they were "associated" with the hippie movement, but because they themselves were hippies.
At the Gates and Carcass both put out far better melodic death metal albums than anything produced by Dark Tranquility or In Flames. I'm assuming you're putting Tool and Mastodon in the "progressive metal" genre, a genre better represented by Demilich. Regarding Larab of God, I'm not generally fond of groove metal, but Exhorder are superior to them.