My dad emailed me this very article asking the very same question. I wrote a whole essay back so I might as well share it with y'all.

I think that, like all "XYZ doesn't mean what you think it means!!!" articles, it overstates the case by quite a bit. They're really talking specifically about the Declaration of Independence, not the Revolution in general. And it's important to bear in mind that King George (who himself is not really the most relevant, Parliament mostly held sway in the UK and George's overblown role in Revolutionary rhetoric is itself propaganda (as /u/storywonker points out)) is not really going to be swayed one way or the other by this thing... its intended audience is other colonists, and its intended purpose is to get them on board with breaking away from their mother country.

There's nothing really groundbreaking in the facts they cite. Fear of slave insurrections (and later just the black underclass committing violence, the first (not the first, see /u/jgrey12 's comment below) some prominent gun control laws in America were passed after then-governor Reagan was greeted by some armed Black Panthers exercising their second amendment rights outside the CA capitol) has been a bedrock aspect of Southern politics since the first slave was brought here until pretty much the Civil Rights movement (and arguably past that, many people will cast the way that most race riots have historically worked--a few black people cause a ruckus, cause some injuries and property damage, and then the entire white population of the city in question descends on the black part of town indiscriminately murdering and burning it to the ground--punitive measures to keep the subservient population in line). It's not like it was ever not a legitimate fear, either--the widely held view that "if black people were free they'd sit indolent, only moving to murder and steal things from white men and rape white women" is obviously not quite on the mark, but the notion that enslaved or just heinously oppressed people rising up if given a legitimate shot at freedom is really not too outlandish.

Native relations is in a similar vein, while things are very complicated based on time and place, generally relations trend towards warfare. The British, who were really only interested in beaver furs, usually had better relationships with the native populations than the Americans, who were moving into fertile land and killing anyone who tried to go live where they used to live because now they were "trespassing" on land that was "legitimately" purchased by a "totally above the level treaty." This tends to lead to conflict. The British only had to promise things like "hey, if you help us keep the colonists in line, we'll draw an absolute line in the sand at the Appalachians, no settlements beyond that (which was, in fact, a promise used to enlist the natives to fight against the French in the Seven Years War, and which was one of the grievances the colonists had with GB in the first place)." So yes, the Indians had very powerful incentives to commit violence on behalf of the British too--not out of savagery, but out of basic survival instinct.

I think where they go a little too clickbaity is that they seek to completely recast the Declaration.. like everything coming out of the "founders," you can't reduce it to a single aim. They were all, like politicians in all times everywhere, looking out for their interests, which differed pretty greatly. Using the single greatest fear of pretty much everyone living on the periphery (the Natives) and the single greatest fear of the Southerners (slave revolts) is just politics 101 to sell the common man on revolution, especially when the British were legitimately leveraging both of those populations to get the colonials back in line. Like they themselves note, TJ wanted to put in a clause awkwardly blaming George III for saddling them with all the slaves that the plantation owners were buying as quickly as they could be brought across the Atlantic, and there were straight-up abolitionists in the room (which is why the "men of their time" defense always seems reallll suspect to me). There were absolutely those who believed the soaring rhetoric about "all men." They were just perfectly willing to sign onto a document saying whatever they needed to in order to get people to join in the revolution.

At the same time there were absolutely people who signed the DoI and the Constitution who firmly believed Sparta was the absolute model for a Republic--Helot slave underclass included. After all, how can a man truly be free to consider the needs of his State if he has to labor for his bread? Freedom means freedom from toil, and if lesser men have to give up ALL their freedom that the greater ones may experience it fully, then that's just a price they'll we'll have to pay. All the better if the people doing the giving can be defined as non-people. Very convenient.

I dunno I think it's good as an article that's more "here's an angle of the DoI that you might not know" rather than "OMG THE REVOLUTION WAS ABOUT SLAVERY GUYS."