My take on the subject:
Having been around cafe racers for the past 33 years, watching them wax and wane in style, I kinda see the current cafe racer movement as a reaction against the modern sportbike. Take a look at a current 600c supersport motorcycle: Over 100 horsepower, 0-60 in less than five seconds, top speed somewhat north of 140mph . . . . . . . . . . and you better bloody well know what you're doing if you're going to ride one.
Now, think of one of the greatest truths in motorcycling, be it modern or vintage:
"It's a hell of a lot more fun to go fast on a slow bike, than it is to go slow on a fast bike."
Add in the average rider's abilities. Bingo!
If you look at the faster available off-the-showroom-floor cafe racers (say a Bonneville Thruxton, as it's an example that I know well) you're talking a bike that'll corner carve nicely, do a good turn of speed (say 110), accelerate faster than 95% of whatever else is one the road (0-60 in 6.5-7 seconds?), and, most importantly, be a forgiving enough bike that Joe-Average-Schmuck can handle without girlfriend or wifey worrying about having to run him to the hospital before the day is through.
Add to that, the style: You're out on the street, somewhat unique, definitely in a minority, and most definitely not just another multicolor leather/mesh clad squid anonymous behind a full-face helmet and tinted shield. Add to that the realization that most cafe racers/Rockers actually build their own bikes rather than just buying off the showroom floor, are carrying forward a sense of history, and are most of all unique . . . . . and it's all awful appealing.
Makes me glad I discovered that spring 1964 Time magazine article luridly reporting on the running battles in Brighton - life hasn't quite been the same.