You keep saying the chief is evil, he is not, as you were already told.
If you are making more of a reference to a paladin summoning Ghaelek, which I have never once seen done, then maybe your argument is a bit more valid. The better part of the code to look to in regards to summoning may be never betray your comrades or cower in fear, since arguably summoning a mob to take your place is cowering or a form of betrayal. But I'd say, so long as the paladin does not flee and abandon the summoned NPC to die, he is within the bounds of acceptable.

But since you're all gung ho about interpreting the code, what about this.
Paladin PC is defending the Fort, imperial invoker/bard whatever comes.
Paladin promptly summon a host of NPC paladin mobs.
Is this a problem?

These are fellow paladins. What harm have you done in bringing them to where the darkness is so they may combat it?
That they may die? So, they accept that as part of their code, as you have stated in #4 (#6 works too)
If anything, those NPCs should be thankful to the PC for bringing them to the darkness.
(looks to be consistent with #4, #5, #6 and maybe even #12)

And how does all of this reconcile with cry of the phoenix?
A paladin is fighting the emperor, maran cries in. Should the paladin tell them to leave? I mean, harm may come to them otherwise.

As an aside, when a goodie summons a goodie, no harm has been brought to the goodie. It is the evil that strikes them and so brings the harm. So summoning a goodie or neutral NPC can not be inherently bad in itself. Putting them in potential harms way maybe, but that's relying on the paladin knowing harm will come to them, which maybe he does, maybe he does not, depending on the situation.