  The upper bound on the ratio of the proton structure functions $F_L/F_2$
tested in the recent paper "The New $F_L$ Measurement from HERA and the Dipole
Model", contrary to what is said therein, does not provide a model-independent
"rigorous" experimental test of the color-dipole picture. The validity of the
theoretical upper bound depends on an ad hoc assumption on the dipole cross
section. -- The analysis in the paper "The New $F_L$ Measurement from HERA and
the Dipole Model" can be reinterpreted as an additional confirmation of the
absolute model-independent prediction from the color-dipole picture of $F_L =
0.27 F_2$.
