Hi. This is because of new regulations regarding ICO, and Dan wishes to follow every possible law.
If you are a U.S citizen, I would recommend purchasing it through an exchange like Kraken or Changelly. Remember it can be secured on an ethereum wallet that you own.
Cheers!
would they take my tokens away if they found out I used VPN to change my country IP?
Nah, but there is a certain degree of additional knowledge and expertise to participate in the ICO if you were to use a VPN. This includes redeeming after buying them, which a lot of people do not know they have to do.
Typically I would suggest buying from an exchange. Cheers
What about Gemini?