It's hardly surprising because the forum has merged all CMS discussion with a blogging platform, so it's natural that most users on here would use WordPress.
Both forums should be separate as the WordPress crowd drowns out CMS discussion, but I wouldn't like to be the person to separate things.
Yes, that's been a pet peeve of mine and for a while. Hawk separated them before the site was reorganized but now they're back together again. Thanks for the Umbraco recommendation. I lost interest in it during the v5 problems but I'll have to give it another whirl.