I certainly agree that it meets the definition, and this wouldn't work out well for a million people to do, but fortunately a million people don't do it.
And what harm will these bottles cause, to anything but human aesthetic? Little to none.
The argument that the ocean is so vast that you can dump anything in it without ill effects was proven wrong decades ago. That's why there are laws against it. If you looked, you can find hundreds of sources to back this up.
I think this was a cool experiment. But people and animals live in these environments, and certainly matters to them when someone tosses non-degradable material in their backyard. How would you like it if people started dumping plastic garbage in your backyard? What about in your house? Surely it's only effects your aesthetic enjoyment, so it doesn't matter right?
What if it's your drinking water?