One major problem with such a study is the very premise of the study. By grouping together diseases such as pneumonia with autism, the study asserts that being autistic should be considered a disease or problem to be solved rather than simply a neurological reality that exists along a diverse neurological spectrum. Anti-vaccine "activists" and researchers heavily demonize autism and autistic people.
"Autism awareness" campaigns often come from non-autistic people, and in them, autistic people are discussed and debated about like a problem to be solved. These "awareness" campaigns mirror cancer awareness campaigns, as if suggesting that autism is akin to cancer. These types of campaigns and "research" are often eugenic in ideology, with researchers boasting potentials to identify probability of autism in fetuses so people can decided if they want to abort the fetus rather than have an autistic child.
The anti-vaccine campaigners and researchers who link vaccines and autism use fear mongering, biased reporting, and ultimately anti-autism ideologies. These kinds of studies directly correlate to oppression against autistic people and neuro-divergent people in general. Rather than embracing a world of neuro-diversity, these kinds of studies continue to enforce a homogenous understanding of brains and continue to enforce oppression and discrimination against people who are considered to not fall within a "normal" neurological classification.