By this rationale any designed "style" that is a refinement or distillation of any other style is going to fall into this umbrella. From the mythic origins of Jeet Kune Do (Tell Bruce Lee's story 30 years from now and some kid will call you an idiot), to a number of weird looking Boxing styles invented by guys like Cus D'Amato and Brendan Ingle. .
Eh but still the story of Bruce inventing his own style because of the short comings he perceived in the art he started with is no where near as far fetched as a secret system practiced among slaves that was passed down and made its way into the penal system and remained unheard of by the general population until a book came out in the late 90s claiming its existence. Lee was just a guy who felt something was flawed and he could tinker with something to make it better.That's generally the sensible origin story for how most combat systems were made
Just as the problem with Cus D'amato and Ingle comparison is both of their systems have been showing to work at the highest level of their sport where as the 52 system has yet to show such a thing.
Besides the problem with the origin claims that signal the usual red flags the other problem i have with 52 is the same problem I see with most traditional Asian martial arts.
1. The evidence of it working is largely reduced to very light sparring clips where they are matched up against their own style and play by their systems own rules. When you find a rare instance of them sparring/fighting hard like TMA it often crumbles into very sloppy brawling that looks like it in no way adds any particular benefit to ring fighting or street defense
2. The 52 guys like the TMA guys like to latch on to high level fighters who don't even have any association with their system to show proof of their system in action. I remember when Machida first broke through and became big you would see Wing Chun guys or Tai Chi guys trying to claim how if you looked closely you can see how Lyoto is demonstrating this punch or this foot work or this principle of their system perfectly . When the reality off the matter is the guy was just doing a text book staple from his own unrelated system
Likewise a boxer cant seemingly move his hands around with feints for even the briefest moment with out the 52 crowd claiming pointing to that as their system in action. Now Jack Johnson or Sweet Pea all the sudden represent the art in its finest. Hell some of the 52 crowd have even claimed the peekaboo was theirs.
Now the likelihood is a group of very savvy capitalists saw a money making opportunity when Douglas Centurys book came out in the late 90s with its vague stories that alluded to this 52 system existing they then attached themselves to this and added a dash of Afrocentrism in and marketed it to a demographic who are fascinated by urban culture and voila you have the 52 as we know it.
Also on a side note as someone who grew up in an urban environment I always found it amusing outsiders were quick to gobble the 52 up. Quite frankly hood people are the biggest bullshitters known to man. Theres so many tall tales through out the community so when you hear a story about some guy who knew another guy who was locked up in the joint and he showed him this stuff that only a select few new to keep themselves safe it comes off like more of the same ol stuff you hear from guys on the corner.