If you ever want to drive yourself crazy, do a search asking if a Christian can do yoga. Go ahead, I’ll wait.
Had enough fun with that yet? One of the things I always see with such a search is that a Christian cannot say “namaste” because it means “I bow to the divine in you.” Since we aren’t gods, the thinking is that we cannot say such a thing.
On the other hand, I’ve met many priests from India. One was our parochial vicar, and a fellow parishioner asked him how to greet him in his native language (Hindi). What did the priest say? “Namaste.” Was he encouraging us to see each other as gods? Hardly! But just as Goodbye comes from the phrase “God be with you,” the etymology of namaste also included a reference to their own religious beliefs. Few know the etymology of goodbye now, or, if they do, few intend the original meaning. In India, at least, the same is true of namaste (in my limited searching on the matter).
All of this reminds me of a story that is often told in my family. One of my older cousins, when she was quite young, had the famous family temper. She was getting angry with her little sister and burst out with, “you! You PEACH COBBLER!!!” In her mind, peach cobbler was about the worst thing you could call someone (and her father encouraged her in that belief). For her, then, calling someone peach cobbler was a bad thing, even though it doesn’t have that meaning.
Similarly, the intent of saying namaste matters. If someone intends to bow to the divine in another when they say it, then that should be avoided. If they simply wish to greet another, there is no harm in it (in my opinion). Of course, one could ask why they need to greet another in a language they don’t even know, and I think most yoga classes would do that just because they think it sounds cool or lends credence to their yoga class being authentically Hindu (spoiler alert: it isn’t. In fact, many asanas were developed because of western influence during the British occupation of India).
I will note that I’m not trying to be relativistic or say that only intent matters. There are things that are objectively, always wrong, regardless of intent. I’m just not sure saying namaste can be included in that, given how its usage has developed in India itself.