Some do, some don't. Some just interpret the phrase differently. Some would say guns are already one of the most regulated products so they're already "well-regulated." Also the Supreme Court ruled in Heller that despite it saying "militia" the phrase really means individual people, meaning individual people have the fundamental right to possess firearms, etc. So, I think most of these people are not disregarding it, they're interpreting it a different way. It's the SCOTUS official interpretation, so it's not like it's a crackpot idea even if it's ultimately wrong. I know I disagree with SCOTUS on a ton of stuff.