I took the time to watch the entire video in order to try and give appropriate feedback and be constructive on this, I won't get into the details of the other people's wrong doing, and try to stick to why I think a DR Reset after 1-2 races like this is warranted.
1. Lap 1 Turn 1, and at 15:00 Mark: You miscalculate your position following the car in front of you, and punt them into Narnia, not this is an accident, but one that could be avoided, you seem to be a bit too aggressive, by that I mean that you are full throttle until the last possible moment, at which point you slam the brakes as hard as you can to make the corner, which in draft, makes it even harder to accomplish.
My Tip for this: Try releasing the throttle 50-60 ft earlier and "coasting" until braking time, this will decrease your chances of having such accidents, and will also allow you to avoid other peoples accidents easier. You will barely lose any speed while coasting due to draft effect, however you will reduce the brake input required to slow down to the necessary speed, increase your time to react to changing situations, and as a BONUS, you will decrease your tire wear by a good margin!
2. You side swiped another mustang on Lap 3 Straight before Turn 1 while moving to overtake the GTR.
My Tip: I noticed you are running the track map as your "widget". I would recommend switching this to the radar, and making it a habit of actually using it (It'll be hard at first to constantly keep a roaming eye on it, but after a while it will become natural. Once you use that, accidents like this will very rarely happen to you.
3. At 11:15, you swerve towards the racing line quite abruptly to prepare for the next corner, and cover the room that was open for the opponent.
My Tip: This is actually a great move to do in real life, where all drivers are aware of their surroundings, however in this game, with mostly casual racers, is would have been safer for your SR to simply keep the inside, take the chicane, possibly lose a position, but likely not, and keep going.
4. At 11:34, Kind of the same situation as the previous corner, would have been safer to simply stay on the middle of the track instead of swerving towards the racing line, you "opened" a door for him to put his nose, and he used you as a moving barrier. Keep in mind, you are not to blame on this incident, I am simply pointing out the way I have been using to avoid these useless SR drops.
I see a lot of people complaining about this, yet, when you look at most of the top guys, the clean guys, they rarely have even slight dips in their SR's, mine is a consistent 99, with the very occasional drop to 90, and rarely do I get contact penalties. I think the SR/DR resets are entirely justified, and furthermore, not strict enough. A 1 week ban from sport races or something along these lines would probably be better, and keep people driving better.
If I take this particular race as an example (and the fact that you said the previous one was similar) this race involved 2 major incidents for which you are at fault, 1 minor incident for which you are at fault, and 2 other "incidents" if you can call them that, which could have been avoided by a safer driving style, and multiply this by 2 races, I don't see a problem with the DR/SR Reset.
Come race with us anytime, and I guarantee you will notice your SR will get on an upwards path, seriously, you are more than welcome to (Any room including XS Speed in the title on American servers)