It's because Pat has configured konsole to launch a 'login shell' (which sources /etc/profile), while other terminal emulators are not configured this way by default.
I don't know what Pat's reason for doing this was - but I'm guessing that it's to avoid problem reports about DIR_COLORS (and other things) not working in runlevel 4 (as kdm/xdm and friends don't source /etc/profile when a user logs in). Whether this was the only reason, or even a reason at all, for that change, I don't know. Perhaps the idea was that most new users (who don't know how to solve this on their own) will be using kde and konsole, and anyone using another window manager and/or terminal emulator should be able to figure it out.
Anyway, one way to solve it is to add this to your $HOME/.bashrc