Note that I am no longer duke of CE and voice my own opinions here. I am not speaking for the entire tribe.
If an ally is being threatened and warred unprovoked, certainly we must defend them even against our NAPs.
In this case however, our some of allies chose to aid PTT in their war against FTR. First off CE has no relations with PTT, and secondly our allies entered this war by choice and not because they had no other options or were under heavy attack.
FTR has in my eyes never made any foul or dishonorable moves and thus we chose not to be a part of this war. Simply because our allies did choose to aid PTT does not mean we on our turn are obliged to aid our allies. This war is was formed due to problems between FTR and PTT, and PTT is not our ally.
In both their announcements our allies (T.F.A and Hatred, for those who did not figure this out yet) stated to support PTT. They chose to support PTT, we choose not to support PTT.
If we do not agree with the argumentation behind this war and see FTR as a honorable tribe which is reasonable in finding diplomatic solutions, then I do not see why we would be obliged to aid our allies in their choice to aid PTT.
Should we aid the allies of our allies now? I think that goes a bit too far.