The writers ARE his fans. Many of them have probably read more Superman than 90% of all comic collectors, and that's before factoring in the firsthand insight that they would get by working for DC. They like Superman enough to make a job out of it, and put their real names out there so that people can anonymously and freely ridicule their ideas and experience. How much they understand is not determined by whether or not we personally agree with them on a given subject.
But it's not as though they constantly have Superman against other heroes. Aside from the JL intro arc and a scuffle with Orion, it wasn't really a thing post flashpoint.
You've compared WW to Superman several times, mentioning that she even takes nukes better. Though you acknowledge that even immediately post crisis, nukes weren't harmful. That constant comparison is just met by the fact that while their powers typically make for an apple and orange scenario (since she's magic) in a direct way she's shown to not have any real advantage.it's not us who are asking for Supes to beat this or that hero. But JLU and other kinds of scenario makes it seem that we are.
Superman is knocked for having these weaknesses, but on an ordinary basis he beats the characters who can access those weaknesses. That's why some consider him overpowered.
Small, unrelated gripe: Cap Atom was totally off in the JLU. He acted nothing like his comic counterpart and the use of his power was underwhelming. I feel like Superman got off easy. The cartoon itself was spectacular, but the individual characters not so much.