I’m no Biblical scholar. But from what I’ve read there are a few things going on here.

1. Sheep and goats in that part of the world, at that time, and even today, are hard to tell apart just by their looks.

2. Shepherds protect sheep from their environment, whereas goatherds protect the environment from their goats. A sheep is led by its shepherd. A goatherd is led by his goat.

It would appear that the point is about the relationship between the sheep and the shepherd that doesn’t with goats.