Neither of those is an effective counter-argument:
1) The existence of expensive cities without rent control doesn't tell us anything about the effect of rent control on rent (cities can be expensive for lots of reasons unrelated to rent control), unless you do a study comparing roughly equivalent expensive cities, some with rent control, and some without. The author didn't do that -- he compared cities with rent control, to cities without, and found that cities with rent control are more expensive. This was bad experimental design.
2) His measurements found that the distributions around the median were different for expensive cities vs. inexpensive ones. But it doesn't really matter that he was comparing the shapes of the distributions, and not their medians, because one can reasonably expect that expensive cities will have a larger contingent of really expensive homes than inexpensive cities, even without the effect of rent control. For that matter, rent control might be the only thing giving the expensive cities a stock of inexpensive housing at all!
Again, for a proper experiment, the author needed to compare equivalently priced cities, varying only the factor of rent control. He didn't do that.
1) The existence of expensive cities without rent control doesn't tell us anything about the effect of rent control on rent (cities can be expensive for lots of reasons unrelated to rent control), unless you do a study comparing roughly equivalent expensive cities, some with rent control, and some without. The author didn't do that -- he compared cities with rent control, to cities without, and found that cities with rent control are more expensive. This was bad experimental design.
2) His measurements found that the distributions around the median were different for expensive cities vs. inexpensive ones. But it doesn't really matter that he was comparing the shapes of the distributions, and not their medians, because one can reasonably expect that expensive cities will have a larger contingent of really expensive homes than inexpensive cities, even without the effect of rent control. For that matter, rent control might be the only thing giving the expensive cities a stock of inexpensive housing at all!
Again, for a proper experiment, the author needed to compare equivalently priced cities, varying only the factor of rent control. He didn't do that.