After discussing this heavily, it seems that something in GNOME has px and pt exactly reversed. "1 pt" = 1/72 inch, i. e. a 10 pt font should have the same physical ruler height *everywhere*, whereas a 10 px font has 10 physical dots on the monitor and thus its size is dependant on the monitor's DPI resolution.
Fonts should not be the same physical size everywhere; by default they ought to be bigger on big screens than on small ones. Thus I agree that 13.333 px is a reasonable default, at least for standard monitors (mobile phone screens are something different, since they usually have much fewer pixels).
After discussing this heavily, it seems that something in GNOME has px and pt exactly reversed. "1 pt" = 1/72 inch, i. e. a 10 pt font should have the same physical ruler height *everywhere*, whereas a 10 px font has 10 physical dots on the monitor and thus its size is dependant on the monitor's DPI resolution.
Fonts should not be the same physical size everywhere; by default they ought to be bigger on big screens than on small ones. Thus I agree that 13.333 px is a reasonable default, at least for standard monitors (mobile phone screens are something different, since they usually have much fewer pixels).