A frequent complaint asexual and aromantic people have to articles about asexuality is the way it often conflates asexuality with aromanticism and assumes aromanticism is kind of a subset of asexuality. It's not; they're two different concepts.
But we, and society in general, are kind of used to treating these orientations as either the same or so intricately woven together you can't easily see where the divide is. Throw in that people's experiences can differ and, well, you get the conflation we often see as well as the erasure that accompanies it.
Which is a lot shorter than the almost-hour I rambled about it. But to be fair, the ramble has more examples and arguments and bits of history and academic theory in it. Yay?