In some ways, yes. And the issue certainly goes beyond just the mode immediate question of inclusion and the moral elements thereof.

Understanding the history of philosophy necessitates considering it in terms of dialogue between philosophers and their ideas. The term "western philosophy" gets used a sort of metagrouping precisely because it's so easy to do so, in part because of Plato's outsized influence over millennia of thought. His dialogues are a sort of common point through time; huge swaths of western philosophy are connected either directly or indirectly to him, even when the works in question aren't direct responses. Some philosophers, such as Plotinus, presuppose knowledge of Plato on a fundamental level; to understand his writing, one must have knowledge of Plato. There are off-hand references to Plato's ideas--beyond just the explicit ones--throughout the Enneads that turn out to be important later, and subject to misunderstandings if missed. The connection of ideas and philosophers is important, and give the impression of a monolithic whole in some ways. That shapes how survey courses in philosophy select their materials, and is often used as a sort of touchstone to help students along. The connection between western philosophy and others like East Asian or Indian philosophy isn't present, or at least not until much later.

On the other hand, Arabic and Islamic philosophers were engaged in an extensive Greek-Arabic Translation Movement to preserve, translate, and engage with Greek texts.[0] Through much of the Middle Ages, the original Greek texts were effectively unavailable: many were lost in the west, but the bigger problem was more in the dearth of Greek literacy. They had partial translations into Latin of some texts, and worked from indirect knowledge of various Greek ideas, but the problems of availability were significant and limiting.[1] Étienne Gilson summed it up as "Plato himself does not appear at all, but Platonism is everywhere."

By contrast, the translation movement starting with al-Kindī at the House of Wisdom in Baghdad (there was also a major movement to translate Greek texts into Syric by Christians living in Syria prior to this as well), both preserved and translated significant numbers of Greek texts, not only preserved and translated the original materials[3] (Aristotle's Metaphysics most of all), the very act of translation helped spur the development of falsafa (Islamic philosophy) in general:

> ...On a technical level, the translations and scientific work conducted in these two centuries [ca. 750 to 950] generated a highly sophisticated scientific language and a massive amount of source material based on the classical tradition that would feed scientific research for the following centuries, not only in the Islamic world but beyond, in Greek and Latin Christendom and, within it, among the Jewish populations as well. On a social level, they created a cultural attitude--a fashion, one could say--that scientific work based on the Greek pattern was something socially valuable and prestigious; the massive amounts of money that were spent on translations and original Arabic works on scientific subjects during the first two centuries of the Abbasids are sufficient proof of this. The continuum of translation and science--the practice, the study, and the sponsoring of it--defined a large percentage of public culture in the first two Abbasid centuries and created a precedent that could never be ignored throughout the medieval period, in either the East or the West.[4]

Starting around the 12th century, both the Arabic translations and Islamic commentaries hit Europe. Commentaries on Aristotle by philosophers such as Ibn Rushd (Averroes) helped shape how Aristotle's texts were received. Avicenna, for example, had a profound impact on philosophy, medicine, and science; even as he disagreed with Avicenna in some areas, he adopted his ideas in others and cited others still (along with other Arabic sources) in multiple writings. This[5] is a pretty interesting overview of some of those connections.

In general, it's safe to say that Arabic philosophy was "transformative" in the West and had a significant role in laying the foundation for the Renaissance. Ignoring it, or--more charitably--not noticing it, is to ignore a key part of western philosophy in doing so. I sincerely doubt the oversight was made on purpose; I can even recognize the reasoning for it. But it's still a useful mistake to point out, even before considering questions of inclusion and representation. Which are also, 100% valid concerns that are debated in philosophy departments. I just didn't focus on them in my reply.

Given the manner in which the information is presented, I can also see the difficulties; it'd mean creating multiple, separate representations in some ways. That said, it's an interesting visualization even if I think there are inherent, significant problems in how it attempts to squash key ideas into single sentence summaries.

0. https://aeon.co/ideas/arabic-translators-did-far-more-than-j...

1. https://plato.stanford.edu/entries/medieval-philosophy/#Avai...

2. https://plato.stanford.edu/entries/arabic-islamic-metaphysic...

3. https://plato.stanford.edu/entries/arabic-islamic-greek/

4. https://books.google.com/books?id=LbqF8z2bq3sC&pg=PA493&dq=a...

5. https://plato.stanford.edu/entries/arabic-islamic-influence/