The formation of the Union was reliant on finding a compromise to the slavery situation. The same people who didn't mention slavery in the Constitution until the 13th Amendment didn't generally run around claiming slavery as the basis for everything they did, but here is just such a description naming names.

https://www.historynet.com/lets-make-a-deal-the-great-compromise.htmThis specifically deals with the ending of the International Slave Trade and how Virginia and Maryland ultimately benefited, just as I said.

I get that this is a thing you don't want to believe. It would mean that many of the illustrious Founders were in the end just greedy men despite their penchant for flowery oratory about equality and rights.