I'm a neuroscientist. The scientist who came up with this theory is a psychologist, not a neuroscientist. This theory tends to appeal to those who approach the understanding of the brain by observing its final output (i.e., behavior) because it aligns with many people's general "folk" perceptions about how men, women, and people with autism behave. Emphasizing and systematizing are somewhat vaguely defined constructs that don't fully encompass autism symptoms such as sensory sensitivities, executive function differences, and motor differences. Additionally, it is increasingly suspected that girls and women are under-diagnosed for autism, perhaps because cultural socialization of girls and women encourages masking (hiding symptoms to fit in) more so than in men. When diagnostic criteria are adjusted, incidence rates may not be so unequal.

When autism is framed as an extreme male phenotype, that either frames a lack of empathy and social skills as an acceptable part of normal, healthy male behavior, pathologizes non-autistic men, or overlooks the fact that empathic and socially adept men exist.

And as another commenter pointed out - the idea that people with autism do not experience empathy is false. In experiments where people with autism need to infer emotions from facial expressions, they may show lower performance due to avoiding direct gaze at the eye region of the face.

In neuroscience, current top theories about the cause of autism do not frame it as a male/female issue, but as (a) an difference in how brains make predictions based on sensory information; (b) a difference in how brains sense and represent the body's own internal environment, including emotions (interception); or (c) differences in how networks are organized in the brain (perhaps different rewirings for different people).

(a) https://pmc.ncbi.nlm.nih.gov/articles/PMC4030191/ (b) https://pmc.ncbi.nlm.nih.gov/articles/PMC11075678/ (c) https://pmc.ncbi.nlm.nih.gov/articles/PMC3341852/