I've never read or don't remember Forever People, so I could be wrong here, but I don't think you can pin down their personal beliefs based on their artistic choices. I think a big difference between them was that Lee's main interest was in characterization, whereas Kirby was concerned with spectacle, situations that would look good on the printed page. As someone who's more interested in the writing than in the art, I sympathize more with the first approach, but they both have their drawbacks. When I reread old Spider-Man comics, I find the Peter Parker material often more interesting than the Spider-Man material, and there have been Kirby books where I thought "this looks great, but it might be the dullest comic book I've ever read."