And I say that it isn't poorly designed.
Of course you don't. What does qualify as a poorly-designed circuit, then?
The difference with Tokyo is that Polyphony was not tied to replicating a real-world circuit, and could have picked anywhere to draw inspiration from. Clubman & SSR5 were similar city circuits, but they both were wider, and featured a greater variety of turns (both in terms of layout and — crucially — speed).
A narrow track on its own isn't bad: Citta di Aria served its purpose in GT4, as a narrow one-on-one event. A high-speed track on its own isn't bad either. Combining them, with absolutely no run-off area, in a game where the
primary focus is multiplayer, is asking for trouble. There's no room for error, and very little room for even avoiding others' errors.
Many of us have been driving Tokyo for weeks at this point. There are plenty of quick, courteous drivers that simply ignore races when Tokyo comes up, because it's far more likely to negatively impact SR than positively (especially as it becomes harder to progress in SR as you get higher).
After experiencing the track myself, I've changed my mind on its general layout for hotlapping — it's still an utter bore visually, but there is certainly a rhythm one needs to be quick there, and there's a level of satisfaction when you succeed. But it's in no way encouraging close, clean racing in 18-car races.
Failure to slow down when approaching a slower car is also driver error. Just because you didn't have the incident doesn't mean that you should have the right to a free pass at ludicrous speed.
Nobody has suggested a "free pass". If there's a pile-up — and you even have time to slow down, given it's a completely high-speed-only circuit — there's more likely to be no way past. Coming to a full stop and letting the cars in front get back into form is the only option here. Whether that's even successful or not (you better hope the other cars behind you do the same)...
that's your concept of ideal racing?
But go ahead, keep telling people that it's their faults when any accidents happen on the track you've yet to race on.
better to let my opponent knock each other off track and see how things go
There is no "off track", it's just "in your way".