We live in an era when all the information that has ever existed is now at our fingertips. While this serves as a great resource for inspiration and a deep well for plagiarism, it also serves as an endless wellspring for annoying gotcha journalism. Recently Facebook has light up with posts about the Airbnb logo being found in an old logo book.
There are three ways this kind of thing happens:
1) It was a lift. It's very tempting when flipping though an old design book or the internet to spot your solution already fully formed and ready to go. Instead of going through the painful process of creating something from nothing, you can start the process 90% finished and simply brush up the colors and shape. This is a bad idea. Not only is it intellectually lazy, but you're gonna get caught. That said, people do it ALL THE TIME. And not just with logos. The hardest part of any design process is the concept and initial form development. Some designers and artists have made whole careers out of lifting stuff and most of us have tried it at least once. Much of the advertising you see consists entirely of reusing other people's ideas, songs, and images.
2) It was "inspired by" the original. This is not the case here, as the two designs pretty much match. But every artist and designer knows exactly what I mean when I say that sometimes you see something and it inspires you to make something similar. That's how art works. Almost nothing is created in a vacuum. The goal here is to be inspired, but then create work that no longer looks like the original. Want to draw with squares like Piet Mondrian? Awesome, go nuts. But don't just make a grid of yellow, blue, and red. Do something else with the idea.
3) It was simply a coincidence. There are no new shapes in the world. Let me be clear about that. All the shapes and colors already exist. Sometimes you can combine them in novel ways, but 99.99% of the time if you dig back far enough you can find pretty much the same thing somewhere else. For example:
In the end the issue is a little more complicated than simply pointing a finger and saying "You stole that!" Maybe they did, maybe they didn't. But the internet isn't known for it's sense of nuance, is it?