This is an error in the application, not the model. Every adjective represents a model. Some we're used to applying as transient, such as emotions (e.g., "happy", "sad"). Others we're used to applying as exclusive and immutable concepts, such as personalities. The latter I think is a mistake. You seem to agree, but make the assumption that someone who identifies personality patterns also makes that mistake. Certainly, this is a pattern you've identified in people :).
You mentioned you've been reading my journal for a long time. You may recall me assessment of Kiersey's book regarding the MBTI. If so, you may remember that my primary criticism of the personality system is that it assumes that people's personalities are set in stone. I strongly disagree with this.
If you read the comments on this post (as well as the Slog article it references) you'll find tons of testimonials of guys saying that they once fit the "nice guy" pattern, but have since changed. That's certainly true of me. And I'm sure the motivations for change as as varied as the men, but it's still a trend we can identify with.