I was banging on about my 22" Faction Zietgiest for yonks and then the S&M came out, followed by the Faction Almero.
One thing I read was that the outside diameter of the wheel including the tyres was how the bikes were classified and whilst I am fully prepared to be corrected, I believe that 22" was decided as the dividing line between "regular" BMX and "cruisers" way back in the day, a ruling that never changed.
At a smidge under 22" outside diameter, the Faction bike wheel and tyre first produced was able to exploit this loophole, but the problem was it was a heavy bike with poor quality components, designed to get the idea of 22" out there. Once the Almera was produced, Faction reduced the wieght and provided the bike as a kit of f&f, wheels and tyres only so you put your own quality parts on it. Again, I think thier custom tyre still measured just under 22" OD so they were still able to sneak into the "regular" class. When S&M produced their bike it was not the same and the larger tyre OD meant it was sat at or just above 22" (I think), making it questionable if it could race with regular 20's.
This GT appears to be another custom 22" rim with custom sized rims and tyres to ensure it is way under the 22" cut-off from what I read?