They left out a critical passage in the GIRM: “305. … Floral decoration should always show moderation and be arranged around the altar rather than on the altar table.”
Nothing should be placed on the *mensa *of the altar other than the things necessary for celebrating the Mass. Candles, crucifix, altar cloths, Missal, corporal, sacred vessels.
Often colloquially it is common to say “on the altar” when one means “in the sanctuary” but there needs to be a better precision to describe where particular items are to be placed for the Mass.
