I would say that philosophies very greatly in terms of context dependency. I'm sure every philosophy is best understood with a little historical context around it, but some benefit more from this than others. For instance, I would consider Socrates' work, which is critical of Athenian society, to be less context dependent than Aristotle's work, which heavily draws upon Athenian customs.
Even with Socrates, however, some context helps. You have to understand, for instance, how different the Greek conception of homosexuality was to the modern one in order to understand a number of the dialogs touching on the subject, and if you don't understand that many of the dialogs were gently mocking well-known celebrities of the day, you miss most of the humor.
Similarly, to really understand Confucius, you need to be steeped in Chinese cultural traditions of the period. On the other hand, the Tao Te Ching, which is oriented away from the mundane world and towards a more mystical view of the cosmos, is less context-dependent despite being highly allusive.
I haven't personally read the Russell book you referenced, but you might compare it to the source philosophies it references and see if those are more or less accessible than his work. After all, in order to understand the Russell, you really need two separate historical contexts --the context for the philosophy, and the context for Russell.