I'm the author of this post, happy to answer any questions. About me: I was formerly a director of product at FB and a founder of Firefox. My YC startup became FB's first acquisition. I'm focusing more on creative writing these days (wrote the Silicon Valley spec script and the Theranos parody that have come up on HN a few times.) Aphantasia was a pretty weird discovery for me given this new focus.
I mulled over that for a bit, and concluded that we all think without words in fact. The thought comes first, then it's translated into words inside our minds. It should be obvious that the brain can only form words after it's formed the thought.
So in your case, I find it impossible to believe that you don't have imagination. I think it might just be inaccessible to you (to your consciousness).
I think most thoughts are in fact unconscious. What we consciously perceive of our own thoughts is just a small part of it, the high level output.
So I'm thinking that for you, the "consciousness barrier" so to speak is just a little higher than it is for most people.