We don’t pretend that it’s winter everywhere at the same time, do we? We don’t use season-zones — we just deal with the fact that the weather is different in different places, and we can certainly deal with the fact that the sun rises at different times in different places.
The flaw in the argument here is that we do actually have "season zones". We don't call it winter everywhere at the same time in spite of the obvious weather differences, we call it winter when it's winter out, much like we call it noon when it's (more or less) noon out.
I use Coordinated Universal Time (UTC) for nearly everything I can: clocks, IRC clients, email clients, servers, and so on. It'd be great if I could use it for regular person-to-person communication as well.
The flaw in the argument here is that we do actually have "season zones". We don't call it winter everywhere at the same time in spite of the obvious weather differences, we call it winter when it's winter out, much like we call it noon when it's (more or less) noon out.