Python apps which initialize threads will end up waking every 1/10th of a
    second, rather than idling properly.
    

Actually, PyGTK applications.  The update manager relies on PyGTK.
Python applications not dependent on PyGTK are unaffected.
Wicd is Python-based:
ii  python                        2.5.2-2    An interactive high-level object-o
ii  python-dbus                   0.83.0-1   simple interprocess messaging syst
ii  python-glade2                 2.12.1-6   GTK+ bindings: Glade support
ii  python-gtk2                   2.12.1-6   Python bindings for the GTK+ widge
ii  python-support                0.8.6      automated rebuilding support for P
ii  wireless-tools                29-1.1     Tools for manipulating Linux Wirel
ii  wpasupplicant                 0.6.4-2    Client support for WPA and WPA2 (I
but doesn't seem to cause problems. Perhaps it's some particular APIs within PyGTK? Or perhaps it's PyGTK and not PyGTK2?

J.E.B.