They didn't mean for the Bill of Rights to cover Englishmen in England, did they? Surely they had some idea of just who these rights were intended to protect? Why can't you see that ?
Legislation only has jurisdiction where it has jurisdiction--usually within the borders of the state represented by the legislating body. That's just a matter of practicality, and even that fortunately is not always adhered to by the US as when it supports foreign insurgents or leaders that are deemed more likely to uphold the natural rights of individuals.
The justification for this nation, the argument for its legitimacy, is described in the Declaration of Independence as an observation of nature "self-evident" and not something that is to be arbitrarily stipulated by some deliberative body. For any government, and the US Constitution, to be founded in truth it must be consistent with nature.
Thus, either the U.S. is illegitimate by the standards of the DoI or else the Constitution is consistent with the fact "that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness."
So, yes, Englishman in England have the right to life, liberty, and the pursuit of happiness, whether or not anyone is able to protect those rights. It is too bad that the US cannot protect everyone's rights, but it can protect the rights of everyone within its borders. You seem to be arguing that since the US cannot protect all people's rights, it should be allowed to violate the rights of some.