in a colloquial sense, from an end user’s perspective, the thing they see is “the algorithm”.
Yes, usually the default or most common method of aggregating posts is what people talk about when saying “the algorithm”
However, any method of sorting posts is by definition an algorithm. “top” is an algorithm, “new” is an algorithm, if you can compare two posts and have a method to choose which one to display first, that right there is an algorithm.
I’d actually argue that the “hot” algorithm is one of the more opaque ones. It sorts posts based on a composition of different metrics, and It’s unclear exactly what these metrics are and how they are combined.
Something I figured out that was handy for guessing some human pieces was trying to figure out what the prompt would have been for generating the image. If I couldn’t formulate with words what the image was, then it was more likely a human artist.
On the other hand, looking at light, shadow, and reflections to see if everything made sense really didn’t help.