Anime fans can get pretty passionate about the characters they love. Some get so passionate, that these fan favorite characters now become subject to intense critique as if they were real. And as Akira Toriyama's Dragon Ball franchise is likely the most well-known anime of all time, its lead character Goku is the target to a lot of this analysis.
Though he is beloved, Goku is very child-like and sometimes very unintelligent. Because the series starts when he is a child, his lack of growth is something some fans don't enjoy-- especially when it comes to his parenting as well as his relationship with his wife. However, looking at the series as a whole, there are a few key factors that might have shaped Goku into who he is and they shouldn't be ignored. While the criticisms of his factor are still very true and valid, they are certainly not baseless.
Goku's childhood was far from normal, and borders on kind of traumatic. He did not ever meet his parents or have them in his life past being a baby. He is adopted by an old man called Grandpa Gohan, who he actually accidentally kills, and then he lives alone. When the original Dragon Ball series starts, he meets another main character named Bulma and they go on a quest together, and he trains in martial arts, keeping in mind Goku is a child at this time. While this may not be too abnormal in the anime world, putting that experience in a real life context will certainly mess with the head of the person who went through it.
With the lack of a parent in his life and a lack of a normal childhood, Goku expresses love in a different way. After his grandfather's death, his trainer Master Roshi became his primary parental figure. In a way, he mimics this with his own children. His time spent with his son Gohan, named after his Grandpa Gohan, involves a lot of training and a lot of fighting. His proudest moments with his son, also tend to involve the son showing his own strength and formidability. While it's not a traditional form of showing love and can make Goku look like he isn't a good dad, he's doing it the only way he knows how.
Goku's entire life basically, has been spent trying to help people and save the world, and at the same time bettering himself and his fighting, getting physically stronger. While he at this point in the series is a stupid level of strong, because everyone he fights just keeps getting stronger and stronger, his mentality doesn't really change throughout. At one point in Dragon Ball Super, he even mentions never having kissed a girl, despite being married to Chi-Chi for many years and having two children. He seems very childish and very unintelligent, which feels weird when he is now a grandpa.
This level of ignorance and, in a way, stupidity, is a major flaw in the series and the character of Goku. After all of these years, it would be good to see him get some real mental growth and development. However, his stunted growth could also be traced back to what he went through as a child. When someone has their conventional childhood taken away from them, it's not uncommon for them to revert back to childhood in their older years. Goku didn't really have a chance to be a normal kid, he didn't have access to education, so he isn't what society would call "conventionally intelligent". He also acts like a child as a grown-up, because he wasn't acting like a child as a kid.
All of this also affects his relationship with his wife Chi-Chi, and this is another aspect of the character that seems to be heavily criticized. To put it bluntly, Goku doesn't seem like a great husband. She doesn't want him indulging in all of these dangerous acts, and she doesn't want him involving their children in it either. However, he does it anyway.
He very often does things his wife not comfortable with and involves their kids in things she's not comfortable with, and Chi Chi is left to kind of handle things on her own. Objectively, it's just not very nice. But similarly to how he expresses love to his children in an unconventional way, Goku does this to keep Chi-Chi, the family, and sometimes the world, free from harm. To him, that could be the ultimate way to show love to a partner. He might not understand that there are other aspects to being a good husband, because it's not what he's ever known.
Despite all of these criticisms, Goku remains a complete fan-favorite among anime fans. Character studies into why he is the way he is have been done before, with some even suspecting he might be on the autism spectrum, but chances are this is just a choice made by the writers. With so much Dragon Ball content out there, it's easy to get lost and try to analyze things to death. Though it can result in getting sucked into a few baseless black holes, it can be beneficial and serve as a good reminder that surface-level perception isn't usually accurate.