I don’t know how technically correct this is, but this is my working understanding:
Concrete is basically just rocks and sand glued together with cement. The rocks make the concrete strong, but they are ugly. If you want to have a nice uniform finish on your concrete, you run a float over it while it is still wet to push all those rocks just under the surface. The “cream” is the wet sand and cement that rises to the top. It’s not as strong, but it has a nice uniform color. The broom texture is made 100% out of cream. Those fine lines are very delicate and you’re always going to take a little bit of that cream off when you wash.
Concrete takes a long time to fully cure, so you have to be particularly careful on new concrete. Maybe up to a year old, you really have to watch it. Good news is that brand new concrete doesn’t usually get dirty that fast. Probably a bigger issue with gas stations and dumpster pads and other commercial stuff that will get dirty very quickly.
But even if it has fully cured, it’s still possible to damage it with enough pressure. Damage will appear as a different color and coarser texture - and it will be in stripes following your spray pattern. As CFH mentioned, a milky color to the water means you are taking off cream.
Over time, the cream will weather away naturally. Sometimes if you look at an old patio, it is smooth right by the wall of the house where it is somewhat protected from the elements. The rest of the patio has a coarser texture where the cream is already gone.