James Robertson points out the difference between "native" OS threads and threads implemented in the language runtime. Some people (as quoted) see mapping language-level threads to OS threads as a good thing.
In part this may come from Java's first implementation of threads (aka "green" threads, a term Jim also applies to VW Smalltalk's threads). These had their share of implementation problems early on and so before long the Java community seemed to gravitate toward an anti-green-thread attitude at the conceptual level. Only now for example is BEA's JRocket JVM *experimenting* with a high-performance non-native thread implementation they call "thin threads" (wisely avoiding the "green" label).