Did we have the technology in the mid 1800s to understand that humans were all the same? Imagine you came from London to Virginia in 1700 and saw American Indians living as hunter gatherers. What empirical basis would you have to say they were the same as Europeans?
In addition to what the other commenter said, the Indians in 1700 Virginia weren't hunter-gatherers. They had farms, money, laws, and government. To the extent that the colonizing English didn't think of them as "the same," well, they felt the same way about the Irish, who are also European.
I mean, to the extent you can have “laws” and “government” without written language, maybe you could say that. The English, meanwhile, had steam engines, buildings nearly 500 feet tall, guns, cities with half a million people, street lighting, and indoor plumbing.
You can have those things without written language; they weren't hunter-gatherers. I don't know what building you're talking about, but as far as I know the Brits didn't have any building nearly that tall in 1700. The Brits didn't have a steam engine in 1700. The Brits recognized, in 1700, that the Indians were people just as much as themselves. This argument of yours projects onto the past an opinion that nobody actually held.
What a comically false thing to say.