My dad used to play red box D&D (which I believe was the first edition ever released). Still has some manuals, which I got the chance to read.
Not only it was encouraged to play humans, it was assumed! You didn’t get to pick a race, only a class. And while the classes of “elf” (think like 5e’s ranger) and “dwarf” (5e’s barbarian, sort of) were a thing, all of the other classes assumed for the player to be a human. You couldn’t play an elf wizard: you either are an elf OR a wizard. Wild stuff, compared to some of the crazy stuff we get to do in modern D&D.
Not familiar, but from what I just read online it looks pretty similar yeah. I believe the idea behind DCC was recreating exactly that simpler old school fantasy.