Dude, get this through your head.
The only one of those "racetracks" which actually exists in the real world in the form of a roadway of any kind is the Tokyo Expressway, and it's a public freeway. It's in no way, shape or form a race track. It's total fantasy setting it up as one. Those other 4 "racetracks" don't exist, there's no road, there's no dirt track, there's nothing. They simply gave them a real world location and designed a track for the game, that's it.
The Tokyo Expressway is akin to the Prague track in Forza which is actually built from real streets and roadways in Prague, those other 4 tracks? They're akin to the Bermese Alps track in Forza which is a representation of the Bermese Alps. Are any of these considered racetracks and does anyone in the Forza community recognize them as such? No, they're fantasy tracks.
Silverstone is a racetrack, Laguna Seca is a racetrack, Brands Hatch is a racetrack, guess what is a public toll-road and also a racetrack? The Nurburgring, but it's an officially certified and sanctioned raceway. None of that shit you're talking about are racetrack anything, and 4/5 of them don't even exist, period.
You're delusional.