First, the usual: Topics such as this are part of the reason I appreciate DT to the extent I do; there's a workable interaction between the fans and the band that really does say something about the humanity of the people playing. Mike's clearly a good person and I'm sorry that people crossed the line of criticism into personal attack. It would upset me too (similar things in my past, though not on this scale, have).
As far as the section in question goes, I agree that the problem is the placement of the vox, not the execution (though as an Opeth fan I did love the growls and would gladly buy a version with them). However, if we remove the vox for a second and just look at the lyrics, there's a bit more subtlety in play there:
It's a miracle he lived
It's a blessing no one died
By the grace of god above
Everyone survived
Now, if you assume the person saying the lines is an arbitrary speaker, the lines do grate a little bit. However, we have to remember that the person saying this is the child (Or adult, either way, JP in this case) and that narrators should never be relied on to give the full story, especially first-person ones (Think Nick Carroway from
The Great Gatsby). Note the earlier lines:
I asked about the others
Is everyone ok?
He told me not to worry
As he turned and looked away
In the growled lines, note the child specifically says that everyone "survived" and that "no one died". He never says that everyone involved in the crash was just peachy and fine. Anything except someone dying as a result of the crash could have happened -- someone could have gotten their spine broken and ended up paralyzed, or someone could be missing a limb or limbs, or there could have been immense mental trauma or permenant burns, etc.
Personally, I think James should have sung those four lines very softly, perhaps over some tritoned, Gothic sounding (Opethian acoustic?) chording -- it would have allowed the subtlety to be more noticeable and would have emphasized the ambiguity and the deliberate holes in the provided information.
But hell, what do I know? It's DT's song and that's just my opinion. However they want to do it -- it's their show, right? (Though I do think that James should have a litle more input on his vocal melodies, but it's not my place to say that).