It's an application of chaos mathematics to personality development. It isn't a rigorous treatment of such, it's a blog post, but it seems fairly reasonable.
Being a blog post and not necessarily intended to end up on Hacker News, shorn of any other context, the author never even used the term "attraction basin", which is the term you'd want to Google if you want to figure out what the author is saying.
If you don't know what an attraction basin is, then yeah, this definitely comes off sounding bad, but if you know what it is it makes sense. Attraction basins are one of those basic concepts from chaos mathematics that, once you realize what they are and why they are, you realize that the world can't help but be full of them in all sorts of places, including human personalities. The world is fundamentally iterative, so patterns that arise in all iterations are relevant all over the place.
Attraction basins are a good reason to expect in advance, sight unseen, that human personalities can actually be fit into a relatively small number of buckets relative to the conceivable number of buckets that could exist. In fact this is true of any generally similar set of entities living in a generally similar environment, including AIs (of similar architectures, not the entire space of possible AIs) and aliens, assuming they also have some sort of "species" categorization as we do. (Which doesn't have to be "DNA genetics", just, a bunch of similar being for whatever reason.) It doesn't tell you what those will be in advance by any means; it just gives you reason to believe that you won't in fact be looking at an "unbiased", uniformly random distribution of personality parameters, but that they will collect around certain attraction basins in general.