As for the accident, there's no telling what happened. Chances are though, that it was due to ignorance. Could have been to either party, or both.
This stuff happens. I don't go to Daytona Bike week anymore because of the number of body bags I saw every year. It is pretty sickening. But, it's not enough to make me quit riding.
I see people do stupid stuff when I'm on the bike, and in the truck. Like itsbob said, all you can do is ride a safely as possible, gain experience with every trip, and be prepared.
You won't be able to avoid every accident, and the cards are stacked against you for being able to ride thru life never having to put a bike down, or having it put down for you. But there are no guarantees in life, at any time. No matter what we do or decide on a daily basis, there are consequences.
With gas over $3.00 gallon, there will be more bikes on the road than ever before. I used to not ride on Fridays as a rule, due to the barfly's being in a hurry to get there, and more times than not, with a buzz on. The gas prices have me going against that rule. I rode last Friday for the first time in years and will probably continue to do so, weather permitting.