That's the government. Was there a government agent present when those thieves broke in to Mr. Smith's home? No? Then via the 10th Amendment those powers devolve to Mr. Smith.
The Constitution guarantees criminals a right to due process.
In a court of law. Were those thieves charged and Mirandized by a court Officer? No? Then your argument does not apply.
This line of argument is the path to madness.
The Fifth Amendment applies to everyone.
A private individual - even if he were the beneficiary of the Tenth Amendment, which he cannot be - cannot use the Tenth Amendment to deprive anyone of their Fifth Amendment right to due process.
The Tenth Amendment cannot abrogate the Fifth.
Due process is an unalterable and irremovable right of every citizen in peacetime.
In a court of law. Were those thieves charged and Mirandized by a court Officer? No? Then your argument does not apply.
Of course it does.
The entire purpose of the Fifth Amendment is prevent extrajudicial proceedings.
Without it, anyone could act as a private judge, jury and executioner to anyone else on any pretext.
This is very basic stuff.