It's a stark reminder that until very recently, "Haha, are you gay?" was all the punchline that a joke needed, even if the joke was coming from the hero of a kid-friendly franchise. It's also weird because Tobey Maguire's Spider-Man isn't really known for his quips, and the ones that he does make in this film are stuff like "It's YOU who's out, Gobby. OUT OF YOUR MIND!" and this shit. It was a weird intersection of homophobia as a comedy staple and writers wanting to remain "comic-friendly" but still not being quite sure what that meant yet.
That this joke would sound insane coming out of Tom Holland's mouth is a pretty cool indicator of how far we've come. Luckily, the scripts for Spider-Man 2 and 3 would cut the lame jokes and play much more to Maguire's strength as Peter Parker, which was being a clumsy dude who convinces Kirsten Dunst to leave her fiance at the altar so he can be emotionally distant with her instead.