Earlier quoted context omitted.
It is more than mixing. It is a reduction in the size of the fat molecules which changes the way the fat acts in the mixture. Shaking the milk before drinking is not the same thing.
Creating an emulsion, which is exactly what homogenization is, does not do anything to the molecules. It reduces the size of the clumps of molecules, which simply allows it to exist in a consistent suspension. It has no effects whatsoever on how those compounds behave in the digestive tract.
Pasteurization is an entirely different matter though. Heat treatment will convert some fraction of lactose into smaller sugars, including its constituent galactose and glucose[2]. This is why ultra-pasteurized can taste a bit sweeter than untreated milk. Pasteurization also inactivates lipases which would otherwise cleave the fat molecules, reducing the likelihood of rancidity[3].
1. https://books.google.com/books?id=1OhFPZ7tFz8C&pg=PA864&lpg=...
2. https://books.google.com/books?hl=en&lr=&id=6Q8mX8DsDe4C&oi=...
3. https://books.google.com/books?id=gJ6jA7LG-bsC&pg=PA276&lpg=...