I don't recall him referring to Dreamweaver but I am quite confident that it actually leads to lower quality sites. For a start it costs a lot of money and means you understand less about what is actually going on. That may make it much harder to fix issues. Also for graphical image manipulation I use gimp which even my children are enthusiastic about. As for yui I chose it because it has a reputation for being good on web accessibility. The conversation was too short to pick up on his attitude to yui specifically.