Thanks.
Your explanation works, too. Marvel is obsessed with keeping Peter Parker as "young and relatable" as possible in the properties it promotes and invests in, since that's how it feels his character should be, so even though Miles is right there for the "young and relatable" paradigm Marvel wants to push with Spider-Man, Marvel won't fully commit to that because Peter Parker and Spider-Man are still synonymous to general audiences, many if not most of whom wouldn't be able to recognize or imagine someone else behind the mask.
All that said, though, since Peter is (or was) the original non-sidekick teen hero, I do wonder what his take on this would be, especially since Jameson in his own series recently called him out in a podcast for going it alone all the time and never seeking help from others or trying to clear the air with the public, media, and/or authorities, which just contributed to the cloud of suspicion around him in-universe. If it was revealed to the public at large that he was a teenager himself when starting out, it could very well be used to strengthen CRADLE's argument against teen heroes, insofar as, "He was never a menace; he was a dumb kid with abilities he didn't understand and who had no business playing superhero without some adult supervision behind him, then maybe his reputation wouldn't be such a mess."