Bluey enjoyment in adults is directly proportional to dissatisfaction with one's own parents. Also it's not a coincidence that pretty much the only TV show about good parenting in the last 20 years has become as popular as it did. The people are starving for a world where we glorify family again, hence adults are going crazy for it. It's not even just autismos and tumblr people, I've seen bodycam footage of bona fide hood niggas from the projects going on tangents about their favourite Bluey character to the interviewing officer. I have witnessed some very unexpected types of people IRL state out of nowhere that they love Bluey. It's a cultural phenomenon at this point.