All MW satellites have the same mass?

from Strigari et al., arXiv:0808.3772

Line-of-sight velocity measurements were used to derive masses within the innermost 300pc of 18 Milky Way dwarf satellites. The above figure is self-explanatory, and surprising: over 5 orders of magnitude in luminosity, there's almost no change in the dark matter+stellar mass. They mention several possible explanations, including a sharp cutoff in star formation efficiency below this halo mass, a characteristic formation time (in CDM models) around the epoch of reionization, or dark matter temperature of >1keV (in WDM models).