Once billed as the Amanda Bynes of S.F. Supervisors, District 5 Supervisor London Breed left Twitter today after battling it out with cycling-rights advocates online. And we're downright crestfallen.

The entire brouhaha started after Patrick Traughber asked, "In your opinion, what is the biggest obstacle to creating safer streets for bicycling?" Innocent question, right? Right. But Breed, known for her flip ways on Twitter, replied that the biggest problem in creating safer street was the "bad behavior of some cyclist."

Oops. Plural fail, let's assume.

Streetsblog responds:

The underlying assumption in this argument is that cycling is an activity for a distinct class of people, rather than just a way of getting around. According to this way of thinking, the city cannot implement proven redesigns that make streets safer for the general population until this “class” exhibits suitable behavior. Imagine if you applied the same logic to car infrastructure: No highway or garage would ever be built until we sorted out all the speeding, failure to yield, and distracted driving that kills thousands of Americans each year.

Lumping “cyclists” together as a class fails to consider the large number of San Franciscans who say they’d ride a bike more if streets were made safer. The perceived bad behavior of some people who already ride bikes should not dictate whether we make streets safer for mothers, kids, and all San Franciscans.

Though she went on to say that she was "not blaming anyone, just providing an answer to a question," later adding, "I'm fighting for changes to our streets for bicyclist daily by promoting responsible and safe behavior on the road," the damage, it seems, was done. Breed took a razor blade to the Twitter artery today, kissing 140 characters of updates goodbye.

Breed, if you recall, was famous for pouring forth such gold nuggets as "if you pay my salary, I want a raise to listen to your bullshit," "you started it," and "ohhhh I'm scared." She will be missed.

This local online scuffle comes on the heels of bike safety being a critical issue in the City, one not taken seriously enough by the powers that be. For example, after a driver killed Amelie Le Moullac, 24, at Sixth and Folsom in SoMa on August 14, SFPD Chief Greg Suhr had to apologize for the unprofessional behavior of Sgt. Richard Ernst, who interrupted a safety rally at the site of the accident to blame the victim.

Speaking of Traughber's question, of all the other S.F. Supervisors and elected officials asked the same question, only two responded: Campos and Avalos.