Cultural appropriation is a nonsense term that immediately undercuts any argument that uses it. All cultures appropriate and assimilate aspects of other cultures. Every culture is already an amalgam of other cultures. Every religion is similarly a mixture of cultural traditions and new practices designed to stand out. Blasphemy is also a nonsense term that should never be applied to outsiders.
None of this is saying that particular examples cannot be on a scale from unseemly to insulting to outright hate. Cultures as well as individuals form opinions on what is acceptable and what is not, even though these are not necessarily consistent or coherent or sensible.
Since snapti claimed - I have no knowledge with what veracity - that his ritual is not even taken from a Jewish ritual but follows a different set of precepts, the accusation of cultural appropriation is even less, um, appropriate. I didn’t read the other thread; maybe he misrepresented himself there. Still, it’s a bracing reminder that the act of calling anything cultural appropriation is full of dangers in itself and maybe leads to worse consequences than the original deed.