For instance, take the GPL: Clause 1 grants permission to distribute verbatim copies, which is obviously not free enough for Debian; it's only Clause 3 that grants you permission to distribute modified copies. The situation seems analogous.
Clause 1 of GPL is not concerned with distribution of modified copies at all. Here, clauses 3 and 4 appear to cover the exact same permission but make incompatible requirements of the distributor.
-- MJR/slef My Opinion Only and possibly not of any group I know. Please http://remember.to/edit_messages on lists to be sure I read http://mjr.towers.org.uk/ gopher://g.towers.org.uk/ slef@jabber.at Creative copyleft computing services via http://www.ttllp.co.uk/