A lot of the German similarities weren't lost on me either. Particularly early on, I'd say most boys and dads had seen enough WWII media to immediately understand that Cobra looked like bad guys, which made it super easy to know who the enemy was, with only the slimmest introduction. And, save for the earliest releases, Cobra always "looked cooler" than the Joes, just like the German uniforms and gear "looked superior" to almost everything in either theater of WWII.
I don't think I have, or ever had, a good answer about why I was/am so hung up on realism with my personal Joe canon. I think it stems from my original attraction to GI Joe. It was the less "far out, more realistic" toy brand to SW or He-Man or even TF at the time. I liked that the OG Joes were basic soldier types - with no super powers or "the force" - that happened to have access to the most advanced (not yet existent) military tech. But they were still (relatively) grounded in a cutting edge military environment, at least for the first few waves. That's what won me over.
I have never had a great explanation about why, in the major depictions of the lore, Cobra was able to fly around in US airspace or set up a town in NJ or inhabit an island in the Gulf of Mexico, without the actual US military simply wiping them off the planet. That sort of thing always bugged me, but, I think my love for the franchise allowed for those kinds of things "because the main US military was busy countering the Soviets," and Cobra was "too dangerous to be handled by anyone besides this special unit."
As things got less grounded and then weirder and weirder, I lost interest. Growing older, discovering girls, working jobs to earn cash and all certainly contributed to my losing interest as well, but I can point to certain divergences from original "realism" that really drove me away, beginning with the weirdness of the the cartoon movie. Not that even the earliest cartoons didn't have some "far out" stuff happening, but up until then, I could tolerate it enough to watch, while still keeping my play canon a lot more "realistic."
I suppose that, particularly this time around, with limited display space and a reserved budget, I am even pickier about my selections than I used to be. I kinda went all-in for the 25th, but can't justify it this time, not at today's prices. Since I've already made the non-completist, non-huge or expensive and non-retro decisions, I have a general "no" policy to anything that can't check either the "wow" or nostalgia boxes for me. That leaves me as probably one of the pickiest Joe CS collectors out there, and I still got more than 50 of them.