But they only guarantee them for citizens, at least until now.Any reference to "citizen" in the US constitution does not refer to the rights of the people but to the right to vote. We all accept that non-citizens can't vote- though there was a time when non-citizens were welcome to vote in the US. ;-)
if you want to be a purist, the Constitution doesn't apply to non-citizens. But it doesn't apply to citizens either. The Constitution is a contract between the federal government and the states; it applies to federal government enumerating the things it may and may not do. The laws of the land apply to all God's children inside (and some would argue outside) US borders ;-)
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
