FWIW milk in Germany is also often (most of the time?) homogenized. And it tastes differently depending on the "manufacturer" (the company, not the cows).

*Also PSA: Europe is many different countries, not a single one like the US. So it doesn't make much sense to say "in Europe", because there are huge differences between countries ;-)

To me the main difference is that in Europe it's possible to get unpasteurized milk whereas in the US it's hard to do so.

I am not talking about "H-Milch" in tetra paks :-)

Both Europe and the US are big places with lots of different rules. In the US roughly half the states ban raw milk sales, another 1/4 allow it to be sold on farms, and the final quarter let it be sold either in farmers markets, stores or both. California is on the less restrictive end -- there's a testing requirement and a warning display requirement but it can be sold anywhere.

Not the first time I have heard of differences between US and European milk on HN: https://news.ycombinator.com/item?id=9323380

Sure, but why conclude that the relevant "something" that is different is homogenization?

I didn't conclude that. It seems the major difference is pasteurization and homogenization so I guess it's one of them or both.

I should add that my observations are mainly about fresh milk from a farm. But even the ultrapasteurized milk they sell in tetra paks is better digestible for me.