Mildly dark concept, endermite are bby enderman and enderman like many animals kill offspring that are not theirs and that is why enderman kill endermites. When they appear bc of teleporting it bc the parent enderman has teleported and not brought the baby with them. Maybe enderman don't recognize their own children and might even kill one that isn't attached to them (how they teleport them). I also headcanon enderman are a telepathic race and that at the larva stage they have no telepathic abilities which is how enderman communicate and recognise each other, so a larva separated from their parents would be unable to get help or be recognised. I dunno