“So Jefferson said. He tells us that South Carolina and Georgia wanted the passage removed, and that he “believes” that Northerners “felt a little tender under those censures” — meaning that he thought some Northerners weren’t happy with the passage — but he doesn’t mention any strong opinions directed against the passage.”
Whether the north had strong opinions, or weak opinions, the northern states voted to adopt a DOI that did not include the condemnation of the slave trade, and did include the King’s exciting slave rebellions as a cause for the revolution.
Later the northern states would adopt a constitution that provided for slavery. The reason: they decided it was in their best interest.
But slavery and the slave trade were big issues to South Carolina and Georgia planters back then, and they were behind the opposition to Jefferson's passage attacking the slave trade.
The degree to which Northerners (or Virginians for that matter) joined the vocal opposition to the paragraph is harder to say. I wouldn't be surprised if one of the Northern delegates had spoken against the passage, but it's also possible Jefferson convinced himself that they had to have been seriously opposed than they were.
Jefferson was the only Southerner on the drafting committee of five members, and apparently the committee approved his original version. Roger Sherman, for example, disliked slavery and assumed that it would eventually be abolished but recognized that the revolution would fail if Southern planters were alienated by attacks on slavery or the slave trade, but it doesn't look like he wanted the passage removed.
Jefferson was a great man, a great soul. He was also a dreamer, and also a partisan. We can value his best ideas and learn from him without necessarily believing everything he said or wrote when he was trying to settle partisan scores.