I had the same thoughts. In fact, by showing the picture of the death star with the equatorial trench displayed so prominently the essay itself sort of primes

I had the same thoughts. In fact, by showing the picture of the death star with the equatorial trench displayed so prominently the essay itself sort of primes you to make an error you might not have otherwise made. But the whole thing was explained in the movie as the essay points out. The animation rotating as is pointed out kind of emphasized that the trench was not the equatorial trench. That's how I remembered it. It was always in my head as a sort of Achilles heel or the culvert in Helms Deep, an important but easily overlooked topological detail.