Why's that?
People were also upset by two things. First, some 1.9 features were backported into 1.8.7, meaning an upgrade from 1.8.6 to 1.8.7 was sometimes painful. Second is numbering confusion. Ruby used to use even numbers for stable releases, and odd numbers for experimental releases. So 1.9 should be experimental, and 1.10 or 2.0 stable. But for various reasons, they didn't want to go to either 1.10 (ever) or 2.0 (yet), so 1.9 will be used for production releases. It has taken a long time for Ruby folks to realize that they should be using 1.9.