why not us ctizien buy btr?

What is the reason for not allowing US investors to buy BTR? Here is what I read in BTR latest quarterly report
Thanks for your response

The ordinary shares of the Company (the “Shares”) have not been, and will not be, registered under the U.S. Securities Act of 1933 (the “U.S. Securities Act”) or the securities laws of any state or other jurisdiction in the United States. In addition,the Company has not been registered under the U.S. Investment Company Act of 1940, as amended (the “U.S. Investment Company Act”), in reliance on the exception provided by section 3(c)(7) thereof. Accordingly, the Shares cannot be held at any time by, or for the account or benefit of, any “U.S. person”, as defined in Rule 902(k) under the U.S. Securities Act, who is not both a “qualified institutional buyer” (“QIB”), as defined in Rule 144A under the U.S. Securities Act, and a “qualified
purchaser” (“QP”), as defined in Section 2(a)(51) of the U.S. Investment Company Act. Any U.S. Person who is not both a QIB and a QP (or any investor who holds Shares for the account or benefit of any U.S. Person who is not both a QIB and QP) is an “Excluded U.S. person”. The Company may require an investor to complete a statutory declaration as to whether they (or any person on whose account or benefit it holds Shares) are an Excluded U.S. person. The Company may treat any investor who does not comply with such a request as an Excluded U.S. person.