Reminds me of the narration in a National Geographic short documentary that I saw in the visitor center of Yellowstone National Park (recollecting from memory): "Lewis and Clark were the first human beings to set foot on this land" ... (and 2 minute later) "... "Native Indians had been living here for thousands of years".

The truly interesting story of the first photographs were back in 1827 when Nicophore Niepce invented the silver halide process that's still in use today. Daguerreotypes came later, were a technological dead end, so toxic, so limited. Niepce has another claim to fame in that he also invented the bicycle. Two big inventions in one lifetime, quite an accomplishment!

Sure, there were probably dozens of people there, but he was the only one who stood still long enough to be captured clearly on the long exposure.

They mention later in the article that the second figure is also visible, but much less distinct. The first figure is unmistakably a person, but if you remove the first figure, the second figure loses context and isn't so clear.

The article makes it very clear that they are talking about the first "recognizable human form" in a photograph, and they go on and on in great detail about what they mean by that.