>>213391542
His is slightly more logistical than Batman's at least. Marvel heroes are perpetually under some measure of PR crisis and are on thin ice constantly. He made Daredevil retire because Kingpin was running New York City as mayor and would be more than happy to use Daredevil killing people as a way to get taxpayer dollars put directly towards killing heroes and re-igniting the superhero registration. Spider-Man himself struggles to maintain a decent reputation and letting people die under his watch makes it even harder.
If he kills, it makes everyone else's lives much harder because a lot of major Marvel villains have outright infrastructural power (as opposed to DC villains who are usually aliens and psychopaths with little to no non-criminal power or are career heisters who themselves refuse to kill or hut innocents meaning it's a much more clear-cut debate).

>>213391590
>You know, except for all the times he does. He's given the Punisher the same speech every time they team up.
Pretty much every time they do is a forced plot contrivance. There are also multiple times where Spider-Man explicitly targets the Punisher. Frank in particular is a common target of Spider-Man's lashouts over it.