The Netherlands and Montenegro are the countries with the tallest people in the world and they are numbers 2 and 3 on the list of highest dairy consumption. This international sports-medicine study is cited
Montenegro in particular is #1 for per-capita smoking deaths worldwide and The Netherlands hit the top 3 while these now-tall people were growing up in the mid-1990s. So now we just proved that dying from smoking is nutritionally beneficial and makes you taller.
The smoking example highlights the problem with the ecological fallacy. You can't lump together everyone from a country and expect any kind of quality data, especially when such data is susceptible to p-hacking (where you take a small sample, like 190 countries rather than millions of individuals, and then just try looking for any correlation between dairy, full-fat dairy, low-fat dairy, red meat, white meat, etc. and height, athletic performance, per-capita Nobel-Prize winners, number of scientific papers on PubMed, etc. until some combination yields the result you're looking for). Not to mention the obvious correlation-causation problem. Why dairy? Why tallest? Why not the link between dairy and strongest bones since that seems to be a more natural claim that I hear about dairy (it's not common for people to argue that dairy made them taller)?
Again, if this is the best epidemiological data that carnists can come up with is some poor aggregation at a meaningless level rather than citing anything of higher quality, then veganism is pretty safe.
Even the study itself disproves the argument because other things were much higher correlated with height than milk across all countries (Table 3b), including total protein and the human development index. So not only does this study control for absolutely nothing, it doesn't even prove the conclusion carnists want.