This the ad hominem fallacy being used to deny the fact that Martin did indeed post the things he is alleged to have posted.
So what?
Martin isn't the "model student" he was portrayed to be by the Left.
Ah, so only "model students" do not deserve to be murdered. Got it.
Why did the Left feel the need to lie about that fact? Especially, if it is irrelevent as you claim that it is.
Surely, it would be as wrong to murder a seventeen year-old as it would be to murder a twelve year-old. Why did the Left keep posting the picture of Martin at age twelve, implying Zimmerman shot a child?