While it’s never really made clear in the movies he’s appeared in, Spider-man possess is easily strong enough to kill a person with a single punch thanks to the whole “proportional powers of a spider thing“. Which is presumably why in the animated Spider-man series from the 90’s, the web slinger wasn’t allowed to punch anyone.
Before that though, a little more about just how hard Spider-man can punch, because it’s actually kind of insane. According to the Marvel wiki, Spider-man is sufficiently strong to bench a tank and could conceivably knock someone the fuck out with a light backhanded slap to the face. Some of Spider-man’s more extreme examples of buffness include punching the shit out of a T-Rex, throwing a truck several hundred feet through the air and lifting an entire fucking building.
According to Spider-man his abs are so ridiculous toned that he once broke a boxer’s wrist by tensing when he hit him in the stomach (we’ve all been there) and has stated on several occasions that he has to purposely act like punches hurt and roll with them convincingly when regular people hit him because if he doesn’t, they’d break their arms and that would be embarrassing.
Which makes the decision of censors in the 90’s to ban Spider-man from doing anything approaching violent sort of ironic, Spider-man already limits his strength in every conceivable way in the comics, so it only makes sense that he’d eventually refrain from punching people at all in at least one incarnation. To get around the strict rules placed on them, which also forbade showing Spider-man hurting pigeons and setting people on fire, the writers and animators were essentially forced to make every fight in the show end in a sweaty grappling match, even in situations where it didn’t really make sense, like when he fought Venom. You know, the guy covered in a slimy, symbiotic alien parasite that presumably smelled like cat turds and wet cheese and also wanted to kill him.
Because kids are idiots, the show was still a huge hit and thanks to its parent pleasing no punching policy, those pesky moral guardians couldn’t really complain about anything the show actually contained except for that one episode where Spider-man inexplicably grows four extra arms and mutates into a giant, constantly screaming man spider.