maybe i think it had more to do with him being a breath of fresh air at the time there were not many anti heroes who worked with the devil (maybe ghost rider but he was never that popular)
If you want to point to one thing that made Spawn hugely popular it was McFarlane's art and the perception that it was a "edgy" and "mature" comic. The story concept is brilliant but the execution more often than not was horrible IMO. Even the stuff written by Gaiman and Moore was pretty weak IMO. I've heard the series did get pretty good as one point, but overall Spawn has been a badly written comic book with good art.
but it is a damn shame you are right that alot of white fans have a problem with black characters. We as black fans accept the medium for all it's white characters but white fans have a hard time accepting one of ours.
Hell yeah they do, but they'll also swear up and down that they don't.
Every time one of the big companies does something significant with a black character they lose their shyt.
Every time a black writer is placed on a book they assume they're a shytty writer that's secretly trying to add more black characters in comics.
God forbid a black writer is writing a black character and references race in any shape or form, then they'll completely lose their shyt, start calling the writer racism, starting saying there's shyt in the comic that isn't there, and telling other people that the comic is "all about how white people are racist".
And the thing is they start talking all that shyt BEFORE even reading the stuff.