I believe the theological error is in the bit about “natural causes disturb otherwise typical biological development”. Properly speaking those are ontological evils. A natural cause can disturb otherwise typical biological development in a number of ways - some leading to severe birth defects, some to mood disorders, some benign, some never noticed, etc.
These are a result of imperfection in the world and not diabolical intervention.
If he’s alleging the same thing for homosexuality then it would be an ontological evil. It’s unfortunate that a child is born with severe mood disorders, or no hands, or homosexual, etc. but it isn’t diabolical. These various abnormalities may or may not make living the good life harder but they are neither supernatural punishment or torment.
Saint Augustine and Saint Thomas Aquinas both comment on this in depth.
Okay, that makes sense. When I saw “natural causes,” I was thinking of factors in the person’s life, including abuse, rather than a purely biological point.