That seems to be Youtube. Since youtube requires you to have an internet connection that means you are connected to a network that may have other devices it may be able to Airplay to which is why its there.
As long as it can pick them up it it will show the icon. There is nothing wrong with that, and as long as you don't select a device to AirPlay to, then you won't be Airplaying.
Also if you let the video load, and then disconnect from any network you were connected to, the AirPlay icon will still be there, but there will be nothing to AirPlay to in the menu.
Why is the existence of that icon an issue? Unless you are actually using it, it is doing absolutely nothing.