Which COMPLETELY ignore the recklessness continuously perpetrated by the CYCLISTS. There's no endangering here, certainly not at the speeds the cyclists should be operating their bikes in a congested situation.
How fast do you really think they are going? 15 mph is a pretty good clip on a recreational (non-racing-style) bike. Most people I’ve run across are doing 12-15 tops.
I don’t notice any complaint in your post about how cars are flying along recklessly at more than twice that speed.
When I regularly rode in London I'd do 7.4 miles in 35 minutes on a Brompton, average of 12.5mph, but factor in red lights, hills etc and peak speed must have been 20.