To me TDKR was frank showing anger on how superman was being written at the time, looks like he wasn't a fan of Brynes run and he was in full support of Alan Moores Superman year One pitch similar to Batman Year One by Frank, but Alan scrapped it and did Watchmen because the Superman Year One pitch was too political for a Superman book and DC said no ( we would have had a very different modern superman if Alan Moore were to write it would we ) strange. I really don't think Frank hates Superman i think he misses the Social Crusader version of Superman from the golden age. Which i cant lie that aspect of superman's character and theme ( and the fact that writers don't write him has a Science Fiction character first then Superhero) has been missing for decades and its only recently the New 52 is bring that version back . Superman wasn't always about hope has people think, yes he did aspire people but there was a time where Superman the character represented the oppressed rising up against the oppressors. He was based on Moses after all the idea of him leading people to defend themselves. Jesus Superman is fairly recent but that's a discussion for another time.
I understand where frank was coming from, i mean yeah some writers forget superman was a Science Fiction character, Silver Age people point to being sci fi but it wasn't pure serious science fiction that asked the big questions . Siegel favorite film was Fritz Lang's Metropolis, which was a movie filled with a lot of themes of class warfare and social and political themes in them has well. Hey im rambling here but i understand where Frank is coming from with his portrayal of Superman. He doesnt even think WW represents what she used to anymore from Franks eyes not mine ( i always felt WW stayed the same in her beliefs to now it hadn't changed)