Look, the ripple effect you seem to keep going on about is nothing more than an additive constant.
Example: A car pulls in front of you. Could be a highway or in the middle of a city - doesn't matter.
Response: You give them enough room, adjusting your speed as necessary to keep your distance behind them the same as you had to the car that was in front of you previously. In dry conditions that is about two seconds - ie a stationary object (road marker, post, roadkill) after being passed by the car in front will take two seconds to be passed by you.
Effect: The only impact this will have on the traffic behind you is that their journey is further delayed by (length of new car) + (distance new car is following traffic IN FRONT OF IT). By delay here, I of course mean as measured in distance, not time. This is a constant length. The traffic is still going at the same speed as before, assuming the new car keeps up, so no problem.
Driving really close to someone when you are paying attention is far less dangerous than causing scores of other drivers behind you to slam brakes, many of whom may be followed by people that were not paying attention.
Correct. And also totally irrelevant. No one maintains a safe distance from the car in front (two seconds in dry conditions) by repeatedly barrelling up and suddenly braking. That would be, as you say, dangerous.
If you are not willing to drive close to someone that forced themselves in front of you, then you are saying you are an inattentive driver, and basically unsafe to drive on modern roadways.
What do you mean by this? That if someone pulls in front of you, you're obliged, by some code, to sit on their tail? I hope that's not what you're saying because that is downright irresponsible and I suggest that any person who advocates such practises is "unsafe to drive on modern roadways".