I found it annoying too... very much like Herbert Butterfield's _The Whig Interpretation of History_, which came to grips with very few actual whigs.
If you're going to do this sort of thing, you need to cite passages from real people, demonstrate that those passages are representative of their thought, and demonstrate that the people you have chosen are in some way important markers of a broader current of thought. Walzer is at best being sloppy.
Brad DeLong