Of course he isn't. We're talking about anticipated arguments of the state.
Do you have any legal support for your position? I think it is contrary to the wording of the statutes. An aggressor can clearly still fit under 776.012. And someone who fits under 776.012 is entitled to immunity under 776.032. Only an aggressor who doesn't fall within (a) or (b) of 776.041 is precluded from using deadly force. If GZ is not the aggressor, or if he is, but he had no lesser force at his disposal or couldn't otherwise extricate himself to avoid the danger he perceived from Trayvon's attack, he's immune under 776.032.
As for the argument that Zimmerman was the aggressor, that's the only way to get Zimmerman under 776.041 in the first place. If O'Mara is arguing that Zimmerman was not the aggressor, then I agree that 776.012 applies.
The cases I've read on the interplay between 776.041(2) and 776.012 (leading to 776.032 immunity) have all denied immunity, but do tend to adopt your position on the interplay, for the sake of argument. I'm not finding the case that I have in mind, but parts of it can be read the other way - that being in 776.041 precludes immunity even if the (a) or (b) exception is found. Ahhh, here it is, State v. Dooley Denial of 776.032 Immunity
(May 11, 2012).
But, the plain language of 776.041 is that the justification
is found if the conditions are met, that is, that the use of force is justified. It does not say that immunity also attaches, just that at some level or at t turn of events in a fight, one has a right to use force in self defense. 776.041 contains all of the elements necessary to find the use of force justified for an aggressor., There is no need to look outside of it. The immunity statute, 776.032, provides immunity from arrest, etc. to a person who meets the requirements of 776.012, 776.013 or 776.031. It could, but does not mention a grant of immunity to a person who meets the justified use of force per 776.041.
I think that is deliberate, and necessary. Assume a fight with no deadly force, but plenty of damages on both sides. Assume one party is the aggressor, but broke off, but his opponent came back for more. Both sides have claims against each other. The law would not give the aggressor immunity from arrest, or from civil action, because the aggressor in fact committed battery, and caused damage.