You find me the difference between acting like the earth is 5000 years old and acting like history only began with American slavery.
You are just being deliberately obstructive.
The 1619 Project doesn't think history started with American slavery. It's a perspective of US history from the frame of slavery which chose as its start point 1619. You may as well argue a history of the 20th century USA thinks that history only began in 1900 and then ended in 1999, and you'd be equally ridiculous.
The 1619 Project is not a declaration of absolute truth, but a way at at looking at things. Most of history is not about absolute truth (too much is unknown, for a start): this is a concept that you should understand from the saying "History is written by the winners". Many alternative and revisionist histories exist precisely because the perspectives and voices of so many - the poor, marginalised, defeated and weak - were excluded from the traditional narrative of history.
I am not sure why you find the idea of bringing in additional voices so repellent. Except possibly that the winners (and their descendants) tend to be unusually touchy about people coming along later and pointing out that the winners' traditional narrative serves the interests of the winners more than everyone else.