I second the questions from others -- where do you live? It really SUCKS that you're treated like this.
I personally CAN'T ride road bikes, I require suspension. There are times of the year when I take to main roads, but my town has made that unnecessary. There's little foot traffic here, so sidewalks ARE a viable option -- and I haven't seen 20 mph in a year and a half, likely never again.
Over the last decade, our pro-cycling mayor has made great strides in making the town more bike-friendly. It used to be JUST LIKE your experience; now, the only "buzzers" I encounter are immigrant drivers.
I'm concerned on two levels -- I HATE seeing anyone drop riding, but I also hate endangerment. All the best to you, bud. Hope you get back to pedaling soon.