Well then more fool the SR people for introducing a bunch of story elements that, by your estimation, cannot be resolved in a motion picture. And of course, you can't help but notice that if this is a Superman who "doesn't do stuff like that," he spends an awful lot of time flirting with Lois, not to mention spying on her and otherwise being a total creeper over someone that he broke things off with.
The Harry thing is like Darth Vader getting away at the end of Star Wars. Yeah, he's out there, but hey, everyone's getting medals except for Chewie! Whereas Superman Returns has started a lot of plots that barely progress at all. Lois is married and...? Superman has a son and...? Not to mention Lex Luthor figures out Superman has a son and... all it leads to is him making some jokes at Superman's expense that Supes doesn't even get. It's all clearly written for a sequel to come along and kick things into high gear, which misses the entire point of making the movie a continuation of the Donner series, which is that the origin story is already done so you don't have to reintroduce all the characters. Frankly, if you need an entire movie to introduce the concept of the love interest having a Muggle boyfriend and a kid, then you've failed as a filmmaker.