I think it would be different if we where reading these stories all of out life in the form of a series of novels. I think my biggest tie up is I've been LOOKING at images of Peter Parker all my life on the comic book page so I kind of have a picture of what Peter should look like. I would feel the same way if they decided in the movie version that once Peter got bit by a radioactive spider he turned purple.
It's no better than making Spidey's suit purple and green. It's just the aesthetic that we're used to and want to see.
The "fact" presupposes that every specific aspect of the visualization in any given depiction is indicative of character. This is a charming ideal, as every aspect of visualization offers the opportunity for the presentation of character, but is never so often exploited.
The varying aspects of the visual depictions (that themselves varied) contain an arguable about of information about the character. Thus this debate. Does a printing error resulting in an inkspot on Peter's face indicate that Peter's character must have a mole? Or even a mole intended. To what degree is that an intrinsic representation of the character?
As with all characters, he's a combination of the textual and visual components through which they have been told and retold. Different viewers/readers latch onto different aspects, with equally valid interpretive weight.
Nicky,
Read the two quotes above yours.
There is no debate. There are certain set characteristics about Peter Parker. Period. End of story. You're treating this character as if he is some ephemeral, undefinable essence. He isn't. There are aspects about Peter Parker and Spiderman that may vary somewhat, but there are also certain core characteristics.
Look, if you want me to get all philosophical on you, I'll say that there is a Platonic essence to Peter Parker and Spiderman and a huge portion of that are the consistent VISUAL elements of the characters. He has brown hair. At least in his youth, he wears glasses. He's white. He generally has short hair (that mullet period in the mid-80s to early-90s notwithstanding...I think pretty much all characters ended up with those at some point during that time...). His suit is red and blue with black "webbing" across it, and with big white otherwise featureless eyes on the suit. Yes, it's debateable as to whether the suit needs to have the webbing underneath his arms (the sort of "flying squirrel" webbing wings). But there are certain generally consistent elements to the visual that represents the character.
Comic book characters are not abstract characters from a novel that leave much to the imagination. They are visually represented which pretty much means EVERYONE sees them in a particular way. Unless you're visually impaired, you can't look at Peter Parker and see a blond. You won't see him as asian, black, hispanic, or whatever. He's white. That's that. Don't believe me? Open a comic book and look for yourself. Unless it's an "alternate universe" (like the black Nick Fury in Marvel's Ultimates line), or there's some in-universe explanation for it (like the Psylocke thing I mentioned), generally speaking the race of a character is one of those consistent elements.
Same with the costume. When characters get new costumes, it usually is explained in one way or another. Maybe the old one was destroyed. Maybe they just decide to go with a new look and have a "How do you like the new me?" panel. But it's not just...there...with no explanation or discussion. Sometimes it absolutely IS to make them more "contemporary" or "accessible." Superman's mullet comes to mind. But even that ends up explained in-universe.
And while you can argue that different viewers and readers find different elements of the characters to be the defining characteristics (IE: is it Peter's nerdiness and social awkwardness that most defines him? Is it his wise-cracking as Spiderman? Is it his sense of honor and duty?) pretty much the brown haired white guy elements aren't up for debate. They're constants. If and when writers and artists decide to change them, they have a significant task ahead of them explaining why they're messing with the established formula. It's not as simple as just "Oh, we cast a different actor." Even in-universe explanations can end up rejected or at least ridiculed by fans. (See also, Superboy-Prime's "retcon pawnch!" to re-create the DC multiverse and basically undo one of the biggest moments in DC comics history.)
The argument about the ink-blot is facetious and I'm calling bull**** on that. Or at least arguing for the sake of arguing. An error in coloring on the lower left-hand panel of page 15 of one issue from 1973 doesn't suddenly establish itself as "canon." A mini-series event culminating with him getting a new costume made of an alien symbiote, ok, THAT is an intentional change and, for at least one generation of comics fans, is an acceptable alternate version of Spiderman. But there are still consistent elements across ALL interpretations of the character, and those elements -- especially the visual ones (like, you know, the fact that he's white) aren't open for negotiation.
So, sorry, but when it comes to the fundamental aspects of a character -- visuals included -- all this attempt to make the debate somehow legitimate just comes across to me as either wrong or just so much disingenuous post-modernist philosophical wanking.