Goodness, I agree that's a lot of incidents. And a lot of irresponsible dog ownership. I do understand the desire to let them roam free now and again but dogs and strangers on bikes is just not a good mix.
It's a constant battle. Chelmsford, where I live, has a town-wide leash requirement, but it's seen as a serving suggestion. Neighboring Carlisle and Westford do not. When we had a dog, we kept her on the leash at all times and everywhere, because she was easily spooked and had a poor recall. One memorable exception was over the line in Westford, on a walk we had taken dozens of times together, without ever seeing so much as a squirrel. Wouldn't you know, a minute after I let her off the leash, she "found" a porcupine with her muzzle. That was a painful experience for her, and for our wallet ($400 vet bill, I think). And they don't learn! Vet said they often see it happen to the same dog again.