A lot of people report a huge improvement in their acne after cutting out dairy. Drinking cow’s milk in large quantities is something humans have only been doing for a few thousand years and there’s quite a bit of evidence we probably shouldn’t.
What evidence? There's a reason the mutation that kept lactase production "on" spread so well. Today many of the healthiest cultures on Earth consume lots of dairy. France with the most butter, Greek with the most cheese, etc.
Vegetarian ≠ Vegan.
Lots of dairy in the standard Vegetarian diet. The link you provided to the Mediterranean diet included lots of dairy (cheese, yogurt, etc.). Also, a lifetime of personal experience says that Seventh-day Adventists eat quite a lot of dairy.
I'm vegan so I know the difference. The Adventists are often cited in nutrition studies and the vegan subgroup of Adventists is the healthiest.
Quoting directly from the link I provided:
If you think the Mediterranean diet looks a little low on dairy foods, you're right. It's certainly lower in dairy than is currently advised in the National Dietary Guidelines
...But traditional Greek Mediterranean populations got calcium from other sources: sardines and other small fish which were eaten with their bones, and from leafy greens (which contain only a little calcium but the large volume of the greens eaten meant the amount added up).
Every country on the Mediterranean consumes an enormous amount of dairy. Greece consumes more cheese per capita than any nation, and Malta, the island in the middle of the med, comes in third.