This is a weird bit of historical revisionism. The US slave trade was abolished in 1807, which was
not the earliest such a law could have been passed. 1776 was. England ended the slave trade the same year (and slavery had clearly been on the way out since
1772, when the first ruling about slavery being illegal in the British isles was made). This ruling may have contributed to the interest in declaring independence from Britain among wealthy US slaveholders, like for example George Washington.
England then abolished slavery in the entire British Colonies in 1833, the US took another 30 years to free southern slaves via the Emancipation Proclamation, and another 2 years beyond that to enact the 13th amendment.
> For all of American history, most people did not own slaves.
This is irrelevant. The powerful and influential did. The people who had control over the government for the most part did. Think I'm lying? More than 3/4 of the signers of the declaration of independence were slaveholders[0].
[0]: https://twitter.com/arlenparsa/status/1168192825848213510