They see them in the movies, and the cartoon shows and the video games. I don't know, maybe they even see them occasionally in the comic books. When they can scrape together enough birthday money and allowance to buy a stack of $3-$4 pamphlets, convince an adult to drive them to the nearest comic book store (which might be quite a ways away, depending on where they live), and succeed in finding some with too few beheadings, dismemberments and rape references for their parents to notice and blanch at.
And, obviously, they see the superheroes in the toy aisles of the various big-box retail outlets their parents shop at, like the Walmart.
How much do they love the superheroes? They just kind of love them in general. They don't have to be the name-brand ones from DC Entertainment and Marvel Entertainment; they just like superheroes, regardless of name or trademark. Which is why Walmart sells not only toys featuring licensed characters from the latest Spider-Man movie and cartoon, and from that Avengers movie everyone liked, or wares featuring Batman and the Justice Leaguers for every age group, they also sell these generic play sets, pictured above.
Six bucks (the cost of 1.5 issues of, say, the brand-new Iron Man or Indestructible Hulk comics) will get you a silver black domino-like mask and matching black and silver cape, or a set of red "power bands" and matching belt.
Or hey, how about this red,
Why, I believe that's the same shield that Agent America or perhaps The Fighting American, used to carry...
*I wasn't shopping there, I swear! I was just accompanying two beloved family members who shop there on the regular. I'm a dues-paying member of a union, and was at my previous day-job too! I ain't no scab! Alright, yes, I did eat some cookies that one of those family members bought. Does that make me a bad person? Oh God, I am a bad person, aren't I?