The autism in this study is ASD. This study doesn't have that much to say about people who don't qualify for a diagnosis, since they would not have qualified to take part in it.
But yes, if you are saying ASD (and not autism itself, as you quoted from the article) is by definition a hindrance, I would be inclined to agree with you, for the reasons you've outlined.
Those four, as studied, are subdivisions of ASD. The paper uses "ASD" and "autism" interchangably (which is I believe standard). Whether they are also subdivisions of something broader is another question. I'm not sure there even is a common scientific definition of autism aside from ASD.
BAP, I think, comes from heritability studies of people who are related to diagnosed people but do not themselves qualify as autistic, they are more likely to have traits associated with ASD despite not being diagnosable.
https://www.verywellhealth.com/broad-autism-phenotype-117279...
The autism in this study is ASD. This study doesn't have that much to say about people who don't qualify for a diagnosis, since they would not have qualified to take part in it.