Svastika is built from su, well, and asti, it is: a word meaning well being or good fortune. In Indian usage it names a mark of auspiciousness drawn at thresholds, on account books and on ritual vessels, and it is old in Hindu, Buddhist and Jain practice alike, long predating any European contact. As a posture name it means the auspicious seat, and it belongs with bhadrasana and the other quality names among the earliest layer of the vocabulary.
The word's twentieth century history in Europe is a separate matter and does not reach back into the Sanskrit texts. The atlas notes the point because a reader meeting the transliterated name for the first time will meet it with that history attached, and because the posture entry and the symbol's modern career are genuinely unconnected: the Hatha Yoga Pradipika was compiled centuries before, in a religious world where the word carried the sense it still carries in South and East Asian practice.
Naming the difficulty is more useful than avoiding the word. The atlas records what the term means in its own tradition, what the posture is, and that the two things a reader may be holding in mind here are not the same thing. Suppressing the name would misrepresent the source, and using it without comment would leave the confusion in place.