I rarely pay attention to lyrics. But the vocals are pretty legible in TFM for a change, and I do have to admit to being like, "Holy shit, that's kind of over the top."
I often wonder why this genre of metal is so stuck in a rut, thematically. It's kind of a one trick pony. It is, after all, possible to enjoy the music of dm and to dislike the message. I'm proof of that. I'm not really what I'd call a christian (probably best described as agnostic these days), but I am sometimes disturbed by dm lyrics as a member of the human race. I understand that christianity has committed atrocities in the name of god, but I don't think retaliatory atrocities are the answer.
There are plenty of other topics out there that are serious and could mesh with dm lyrics. Philosophy is the go to, of course (which often winds its way back to religion) and science (a la Vintersorg, I guess...not dm, of course). I started a thread some time ago about whether metal's lyrics need be brutal, thinking of my own children. For me, the question of whether or not I'm okay with dm lyrics and such came from the fact that I don't want my daughters to hear them.
I know that positive, life-affirming death metal would be a contradiction in terms, but if it existed and was good, I'd prefer to listen to it over violent, hate-filled, negative music, the music being equal.