Sometimes you have to take chances, like trying to out-brake and pass on the inside when there is a clearly open lane to do so(like the video). This isn't limited to passing, though. If you aren't going to do it, you will probably never be successful. Any driver knows that they will not always just be given a position, they have to push for it. Now... that does not excuse any contact. It just happens sometimes. Humans make mistakes, and technology sometimes fails. If you were to ask a race car driver, "Have you ever taken a calculated risk?", and they answered no, they'd be lying(or not interested in winning or getting to the next level). Every amateur and professional racer I've asked has answered yes. Clean racing is very complex, but values and ethics are a large part of it, not just a lack of contact.
I agree with most of what you say and I think it highlights for me, the difference between incident free driving and calamity...lol. I do most of my passing in two ways.
1. On a straight using the draft.
2. Pressuring the driver in front until he makes a mistake, but without contact.
A monkey could pass using the draft effect in GT5, especially the strong draft. Get within a second at the start of most straightaways and you can pass somewhere before the next corner.
Pressuring the driver in front to me involves staying close, the odd little bump on the straight sometimes to let him know I'm there, "
showing" pass but not taking it etc. It's a psychological battle trying to throw the guy in front of me off his game. It works quite often.
So when it's the last lap, and I'm head to head with one or more drivers, and I know I cannot pass using the draft and no one's making any mistakes, then
I choose not to stick my nose in front of his rear bumper (not a legal maneuvre in the GTPlanet Racing Rules anyway), nor bump him from behind entering a corner. That's my choice that I'd rather lose fair and square than make a high risk maneuvre and take us both out, or take him out and not me, and go on to a tainted victory.
At most tracks there is an opportunity for a late draft pass. At Tsukuba for instance, get a run out of the last hairpin and draft up to parellel or beyond entering the final corner. At Deep Forest get a run out of the last corner and draft by. At Road Course Indy, Daytona etc. you can draft right up to the S/F line with a long run up. On tracks that don't offer that type of pass, you have to pass earlier. Trial Mountain comes to mind. You have to set up a pass on the back straight, take the lead and then run a defensive line to hold on.
My point is, there is a way to win at every track, without making high risk maneuvres that result in contact. You have to take a whole race approach and know the track, not just fly by the seat of your pants and win at all costs, the costs being borne mostly by your fellow racers in terms of their race enjoyment. That's not racing, that's arcade, and the whole point of this GT5 exercise is to move towards real racing, not arcade racing.
The extreme irony in that statement! Evolved draft effect for evolved monkeys! 
Good one.
