Uh, no I don't know.
These people attempt to cover their indecision or inconsistency by a false appeal to authority, namely Ralph Waldo Emerson (a dubious authority, but a very quotable one). However, this reference to Emerson's essay "Self Reliance" misses the point, in large because it's so frequently misquoted.
So what did Emerson mean when his said, "A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines"? Did he mean that we should vascillate willy-nilly or not attempt to apply rigor to our thought and behavior? No. Quite the opposite. The point was to follow the truth where ever it leads us, to the point of abandoning those beliefs we claimed before. To cling to a position out of the desire for consistency alone is foolish. To cling to something because it is true is not.
The same sort of thought frequently infects those who attack Catholic devotions such as the Rosary as being "vain repetition." This particular phrase comes from the King James translation of Matthew 6:7:
But when ye pray, use not vain repetitions, as the heathen do: for they think that they shall be heard for their much speaking.
This verse is often taken to mean that we should not use repetition in prayer, or that we shouldn't use rote prayer at all. There are two problems with this perspective. The first is that what the KJV translation renders as "vain repetition," other translations render differently. For example, the Revised Standard Version translates the same verse as follows:
And in praying do not heap up empty phrases as the Gentiles do; for they think that they will be heard for their many words.
And when you are praying, speak not much, as the heathens. For they think that in their much speaking they may be heard.
The NIV even seems to be more in line with the Catholic translations than the KJV:
And when you pray, do not keep on babbling like pagans, for they think they will be heard because of their many words.
So the accuracy of the translation "vain repetition" is rather sketchy. Even if it weren't, what does the phrase "vain repetitions" mean? Does it mean that all repetition is vain, or does it refer specifically to repetitions that are vain? One sense is restrictive and applies to a specific set of repetitions, while the other classifies all repetitions as vain. If nothing else, the superfluity of translations that refer to babbling or meaningless repetitions should indicate that Christ was referring not to all repetition but to repetition that is not from the heart, hence, meaningless or vain.
The devotion most commonly targeted as "vain repetition" is the Rosary. That the devotion is repetitious is undeniable. However, is it vain? Or is it unscriptural? An examination of the two dimensions of the Rosary (prayers and meditations) show that it is not unscriptural. The Lord's Prayer, of course, is included in the gospels of Matthew and Luke. While the Glory Be isn't quoted in scripture directly, the realities it reflects can certainly not be considered unscriptural.
Then what about the prayer that is most repeated in the Rosary, the Hail Mary? This prayer comes right out of the Gospel of Luke, chapter 1, verses 28 ("Hail, full of grace!") and 42 ("Blessed are you among women and blessed is the fruuit of your womb!"). The only part that is not scriptural, strictly speaking, is our request for Mary's prayers. For Catholics who believe that saints in Heaven (St. Paul's "cloud of witnesses") are living, spiritual entities, there is little difference between requesting prayers from a saint or from a friend on Earth (except that the prayers of a saint may be more efficacious, coming from one perfected in Christ). So how could reciting scripture and requesting prayers be considered a vain activity?
The other component of the Rosary, one of which most non-Catholics are unaware, is the meditation on the mysteries of Christ's life, death, and resurrection. While one of the Glorious mysteries (the Assumption) is not strictly scriptural, it is borne out in the traditions of both the Eastern and Western Church, albeit under different names. Every other mystery has some connection to an event or scene in scripture. In a very real sense, the mysteries of the Rosary are a meditation on the Gospel itself.
When done with the right intent and attention, the Rosary is quite simply one of the most scriptural and most spiritual devotions we have.