RAW is rules as written.
At the beginning of the Combat Move phase, you may
already have sea units in spaces containing enemy units that
were there at the start of your turn. For example, an enemy
may have built new sea units in a sea zone where you have
surface warships. When your turn comes around again, you
are sharing that sea zone with enemy forces.
If you are sharing a sea zone with enemy surface warships
(not submarines and/or transports), this situation requires
you to do one of the following:
� Remain in the sea zone and conduct combat,
� Leave the sea zone, load units if desired, and conduct
� Leave the sea zone, load units, and return to the same sea
zone to conduct combat (you cannot load units while in a
hostile sea zone), or
� Leave the sea zone and conduct no combat.
Once these sea units have moved and/or participated in
combat, they cannot move or participate in the Noncombat
Move phase of the turn.
Here is what is not clear. 1st it states surface warships which transports are not. 2nd I am choosing to remain in the seazone, it does not state I cannot load units if I decide to do that.
A transport can load units while in any friendly sea zone along its route, including the sea zone it started in.
This is under the transport section in combat movement. When playing by the rules as written you have to assume both statements are true and in order for both statements to be true, I can load in an occupied sea zone.
The second half of that last statement I last quoted is not repeating the first half of the statement in that sentence, that would be redundant. A route by definition includes the start and the finish, the including therefor implies I can load in contested sea zones provided my transports started there.