You ever hear the argument that there needs to be more role models in comics for African-Americans, Asians, women, homosexuals, etc.? That part of the problem with mainstream comics is that it's so filled with Caucasian men that it's harder than it should be to draw in those other fans? That they look at those comics and say, "Where are the heroes that look like me?"
It was something I was aware of and understood, certainly, but speaking as a white male, I found it difficult to relate to. After all, most comic book heroes do look like me in that regard. But somehow, and I don't know what caused me to remember this, but my very first favorite superhero was Sun Boy from the Legion of the Super-Heroes. Not because I liked his powers, or he had a cool costume, but because he had red hair. Just like me.
I remember thinking as a kid that was kind of a silly notion. I really knew nothing about the character; he wasn't one of the big names in the Legion stories in the first place, and I didn't have very many Legion comics anyway. But he was the only hero that had red hair. In fact, the only other comic characters I knew that had red hair were Jimmy Olsen and Archie Andrews, and neither of them came across as particularly strong, positive characters. But, nonetheless, I still liked Sun Boy.
Eventually, I "graduated" to Marvel comics. I didn't see ANY redheads there, but the Human Torch had kind of similar powers to Sun Boy and the Torch remained my favorite characters for years.
At some point in the early/mid-1980s, my dad picked up some of the ElfQuest graphic novels. I read them in my free time, and was struck by everything about the story. And who stood out as my favorite character? Redlance.
To be fair, I felt more in touch with the only male lead character in ElfQuest (at the time) that was NOT a warrior but an artist, and I appreciated the kind of hippie vibe that he and his soulmate Nightfall had. But it was by no means lost on me that, of all the characters in the story, Redlance was the one who looked most like me.
A few decades on now, and my hair's gotten more of a dirty-strawberry-blonde look to it. And it's been getting peppered with white the past few years as well. Add on top of that a receding (receded?) hairline, and I really look nothing like those characters any more. Would I have still gotten into comics if I hadn't seen those ginger characters? Almost certainly. I may have gravitated towards some other characters -- maybe Clark Kent because he wore glasses or Spider-Man because he was picked on in school. But the further removed you are as a reader from feeling a connection with the character, the less likely you are to be involved. And in comics, that connection is going to be sparked, at least in part, by the character's visual appearance; it's the most easily and quickly read part of who they are.
While I always appreciated why people bemoan the lack of characters that "look like me", the sudden recollection of my early favorites makes it a lot more visceral. Maybe a trip through your own earliest comic memories might trigger a similar understanding.