In my own personal experience -- which I presented immediately after the sentence you quoted -- I didn't originally understand how to visualize, and then later discovered more about how to actually visualize.

So clearly it's not like the case where a person is born without a sense of smell, because in that case nobody's going to present an "at first I didn't know how to smell, but now I do" story.

I'm not saying that all people who experience aphantasia are "just doing it wrong." But I can assert that in at least some cases it is a skill issue, because one of those cases was my own case.

Sounds like you have aphantasia but you’ve convinced yourself that you don’t.

Here’s a simple question: how close are your waking visualizations to images you see in vivid dreams? From what you’ve said, assuming you do experience vivid dreams sometimes, it sounds like the answer is “not very”.

Many people without aphantasia report waking imagery quite close or at least comparable to what they experience in dreams. If that’s not the case for you, that’s consistent with aphantasia.

The OP article does a decent job of describing it. I recommend reading it, if you haven’t already. What you’ve described matches how it describes aphantasia very closely.