Fat vs vegan

All depends what kind of skin you have.

Animal fats work more on surface.
Easier and faster, the lather is slick and cushony.
But they will not really increase skin conditioning.

Vegetal fats work more in deep.
Exactly the opposite.

For my dermatitis, the seconds work better.
But I love the feeling of the first too.

You are spot on. For instance Alepo soaps had been used to treat dermatitis for thousands years. Maybe there are some animal fats that have similar properties, like Emu oil, but they are just not used in shaving soaps. I believe that the principal reason is the monopoly of the pharmaceutical empire. If the natural way wasn't persecuted and censured there would have been more natural soaps and balms for chronic conditions.

If the natural way ...

Hemlock is a very present herb in Nature.
In fact, Aristotle died naturally.
The natural way is romantic.
But overrated.