Here's why I think they exclude foreigners:
1) It's nearly impossible to spend < $10,000 for foreigners to get 1K unless they fly to the US and do lots of cheap flights. The < 10 cpm fares are typically domestic coast to coast for ~$300 so you earn 5,000 miles for $300. The cheapest K fare for LAX-NRT is $1250 not including taxes (does include YQ). So that's more than 10 cpm: 11,000 miles for $1250.
2) It's unreasonable to expect foreigners to consistently buy UA 016 tickets for non-UA Star Alliance.
I also think 2) is unreasonable for "global" people like myself. Fortunately, I have legitimate non-US addresses and my mileage plus address is currently in Japan.
Counting PQD for RTW tickets is going to be a huge mess. And it's outrageous considering that if you call UA and say that you want to buy a RTW starting in Japan with a first leg to Frankfurt they will say, sorry, we can't sell that to you. Meanwhile there is a great tool on the *A website that allows easy planning and booking with knowledgeable people who answer the phone instantly. They are LH staff and the tickets are LH stock.