This is only partially correct; the blacks had not voluntarily signed on, they were actually pirated from a slave ship.
Virginia had no active slave trade, but the black angolans were used to barter for provisions.
There are questions about whether the Virginian’s who were part of this trade saw the men as “slaves”, or even as “black”. But from the Angolan perspective, they were slaves, forcibly removed from their country.
They simply were less oppressed, having been “rescued” by the pirates and relocated to a slightly more hospitable group of people than where they were being taken.
They also weren’t the first blacks to be forcibly brought to this country, or to virginia.
The Angola perspective is irrelevant to the laws of Jamestown in 1619. What counted for the Africans is how Virginia colonial law saw them, and until 1655 and the Casor decision there was no chattel slavery in Virginia.
“They also weren’t the first blacks to be forcibly brought to this country, or to virginia.”
And your source for that is?