Maybe because it WAS consistent until the FF devs made the choice to change it? As I said before, if they decided to change the role of the right-click to no longer bring up a context menu, would you be ok with that as well? What about the difference between clicking on text in a browser article or clicking into a textarea? Those also have different roles, so if the devs decide that a user single-clicking into the textarea should automatically select the entire field, would that make sense to you? If I click on any text anywhere in any application, I expect to get the same results, and not have to remember how every application handles that click differently. Sure if I was clicking on something other than text then different actions might make sense in different applications, but the idea of a single click on the address bar selecting everything is akin to clicking an icon on my desktop and having all the surrounding icons also getting selected – it just doesn’t make sense and it’s not consistent with a single click in any other application.