I slightly disagree even with that. I don't think it's about camp and I don't think it's about being silly, I think that people need to be able to read the comics or watch the movies and come away with a good feeling-that there were heroes, there were villains, the villains did bad things and the hero saved the day. We can all leave feeling happy when the good guy punches the bad guy a lot. Silly movies can accomplish that-look at Guardians of the Galaxy, it took itself seriously for about 5 minutes, then Chris Pratt started dancing through ancient ruins. Look at Ant-Man, it was funny, but there was also a big bad guy that needed punching, and lots of it.
If we got an Aquaman movie where he stuck to his characterization in Brave and the Bold, where he was a loud and boisterous bruiser style of character, I think it would be pretty well received. Just imagine like 20 bad guys coming up to Aquaman and he shouts "why, I'll take you ALL on!" and then there's a big fight scene, that would be fun!
Bottom line, superheroes need to be fun. Because people like fun.