[asveikau]

I think the broken assumption is that they make these decisions on the granularity of a channel rather than a video. A channel like Dave Plummer that talks about multiple topics (tech and neurodiversity) gets neurodiversity suggestions even if that's not the video you've watched within the channel.

I assume some followers watch only the tech, others watch only the neurodiversity topics, and some watch both.

You could have a recommendation engine that works in almost exactly the same way as Google's that suffers less from this problem.