Drivers and cyclists have a complicated and difficult relationship. Often, the two groups really do not like each other all that much. The resentment that drivers feel for cyclists is often what leads to accidents, and it's safe to say that cyclists get hurt in these crashes far more often than drivers.
One big issue is that drivers often take offense to what is really no more than a mild inconvenience. For instance, one rider said that drivers would cut him off on his bike if it helped them get to their destination just a few seconds faster. They'd tailgate and honk their horns if he was riding slower than they wanted to drive, even if rushing ahead just meant waiting for longer at the next red light.
When they could get around, drivers often would not move to the side and give him sufficient space. Instead, they would pass him with just inches to spare. They did not want to share the road and may have felt frustrated that the bike was even there, so they crowded him to show their displeasure.
This entire mindset is very dangerous. Drivers need to share the road. They need to understand how vulnerable cyclists are. Above all else, they need to make sure they do not give more importance to resolving that minor inconvenience than they do to a cyclist's life. No schedule that anyone feels they have to keep is more important than a person's life.
Unfortunately, these accidents just keep happening, and it is important for cyclists to know what rights they have if they get hurt.