did the comics ever explain magic as a weakness for supes?

Its not that he has a weakness, its simply he doesnt have a resistance to spells and stuff.

 

Superman's powers are based on the scientific laws of the universe. Magic blows a hole in those laws. It's pretty simple.

 

Yep thats it.

To expand. Someone like marvel is enhanced by magic(and has resistance to). So outside his bolts(which is quite a bit magically enhanced). His punches dont do any special damage. Its like superman. He's solar powered but his punches dont feel like the sun is hitting the object.

 

Captain Marvel's punches have had a more pronounced effect due to the magic energy that powers him in the past.