Why did parents and intellectuals object to comic books in the 30s?

Nowadays, comic books are commonplace, with people of all ages enjoying the different genres offered in the illustration-focused style. However, comic books were not always accepted freely as appropriate entertainment. 1929 was when the first collection of comics was published, and when the golden age of comics rolled in with the 1930s, there was much controversy surrounding the matter. Many groups voiced their objections to comic books, including educators, parents, churches, civic groups, as well as mental health experts. 
Educators believed that comic books would have negative effects on their students’ abilities, whether in their reading or in their taste for literature. Parents, churches, and civic groups were concerned about the possibility of children absorbing what they considered immoral content. Mental health experts were worried about the possibility of children becoming desensitized to violence, since violent behavior was rampant throughout many comic books. (This same desensitization to violence is something that is often studied nowadays in regard to the effect of movies and television on children.)
When superhero comics came about, objections seemed to die down. However, when the superhero craze began to fade, controversy rose again, and in 1954, the Comics Code Authority was formed to regulate the contents of comic books in the United States. Over the years, publishers have broken off from the CCA, and by 2011, the CCA became obsolete when the last publisher abandoned it.
http://cbldf.org/comics-code-history-the-seal-of-approval/

https://comicsalliance.com/history-comics-code-authority/