mumbo-jumbo is a term for nonsense, or the object of false worship. It is not typically used to mean rote words as would be implied (in this case) as used by people showing acquiescence to a mighty ruler, or some sort of religious fervor. It could be described as mumbo-jumbo, nonsense words of no value, but the people saying the rote things would not see them as nonsense. I would describe those folks on bended-knees as offering the appropriate rites (or sacraments). They are not truly mumbo-jumbo, although they might appear to be to an outsider.
Mumbo-jumbo does get used for rites invoking the magical or the supernatural, so it is not inappropriate for description of religious rites, but it is definitely seen as extremely dismissive of those rites as having any real meaning or value, so it can be taken as an offensive declaration to those who believe in their rites.
It does also carry a bit of a racist history that is mostly not recognized or intended by anyone who uses the phrase. Mumbo-jumbo literally refers to an idol of some African religion or other, rather than the appeal to that idol, but we tend to now use the word to refer to the appeal itself, rather than the idol (the "false" god).
When I say "false", I used quotes because I cannot declare what god is true or not for you or anyone else. It is not my place to decide that, but people have, and people do make those determinations for others. I don't particularly like when they do.