If you'd read the issue, Galactus was at his weakest ever. He was probably just a peg above Thanos in power at the time. He was literally near the brink of death from hunger. As I said,
THE WASP helped out against Galactus, by distracting him. Why couldn't Spidey do the same thing? He did so against Omega, Thanos' Galactus clone in Infinity Abyss, ditto the Infinity Union-weilding Nebula, left himself open to attack by himself attacking Thanos to knock him off-balance (giving Thor 2 an opening to lay a real hurting on him) in IG, and did much the same against The Stranger.
Spidey could've at least web-tripped him or leapt around and annoyed him. Everyone there, except for Dr. Strange, Thor, Iron Man, The Thing, and maybe The Human Torch or Sue was completely useless as far as truly
hurting Galactus (in fact even they were causing only minor damage), but Cap, Wasp, and Reed were providing strategies and distractions, which were helping their team.
I think one of the few
good parts of "Sins Past" was that footage of Spidey's first "battle" with Galactus, where he was holding onto his foot as he was walking, yelling "Hey! Hey! Hey hey hey!"
Oh, and I do agree about the majority of Byrne's FF run --- some of Byrne's best stuff. It was a funny scene, but it would've worked better if Galactus had been at full power, and everyone except for Thor, Dr. Strange, and Iron Man stayed out of the direct confrontation the same as Spidey did.
I always enjoyed when Spidey, while briefly "dead", decided to slug Thanos (weilding The Infinity Gauntlet at the time) just to spite him.
Oh, and Figgnuts, Bendis himself said pretty much the exact same thing in his Wizard interview.
-Jimmy