With the best will in the world, if you're a DR D driver you really shouldn't be looking at your number, much less worrying about it. You're almost always going to be racing against the same people whether your DR is 1 or 1000 so it doesn't make any difference.
If you want to race against good and clean drivers then the only thing to do is be a good and clean driver yourself. Put more time into practicing and qualifying, you'll start further up the grid (whether in daily or FIA races) and you'll deal less with people who are intentionally or otherwise disruptive.
Remember, the skill level is lower at DR D and people will make mistakes. Not everyone who hits you will be doing it deliberately. Not everyone who's fighting for position, 1st or 10th, will have the temperament to be able to hold their lines and always be sure they're giving others enough space. Contact happens.
For the most part you can tell who hits other cars deliberately and who does it accidentally. When you're near the former, look out for it and react to it. If you see someone ramming off people who get near them, are you going to be surprised if you catch up to them and they then try to hit you off? Are you going to be angry at them for hitting you, or angry at yourself for knowing it was coming and putting yourself in that position anyway? When you're still learning how to race and drive yourself you have to factor this in - the field around you is always different, and requires different responses for different situations.
Pretty much everyone on here who isn't an alien has reached the level they have by spending time with the game, cars, tracks and learning from their own experiences and the accounts of others, whether it's people putting clips up here and asking for feedback or watching people like Super GT and Tidgney on youtube who race in high splits and explain how they race - why their car is where it is at various points, how they react to other drivers on track, what their strategies are, that sort of thing.
Focus on your own driving. If you do that, you'll drive better. If your race is disrupted by other people, that's their problem, not yours. Learn from it, avoid situations like that in the future and keep focusing on your own driving.