This isn't just a to protect the cyclists from being hit by cars, but to protect pedestrians from being hit by cyclists.
I'm sorry but my experience of living in London in the past 4 years pretty much made me hate cyclists with passion.
I find them considerably more dangerous and pesky than cars, they simply ignore all rules whether it's not giving a flying duck about the red signal at a bike lane while pedestrians have the green light to cross the street, utterly ignoring no bikes allowed in the run/walk only paths in Hyde Park or by interchanging road, bike lane, sidewalk and even the crosswalk at will with nill consideration to pedestrians and a shitty attitude to boot.
I'm constantly buzzed off green lights (to me) by cyclists that cycle at high speeds because they could not be arsed to honor a red light, I've been hit by bikes more than once in these 4 years, and just over the weekend I've seen a guy on a rental metro bike hit a baby carriage (empty one as far as i could tell) in Hyde Park because they were in a no-bike zone and came out a turn which has no visibility whatsoever.
I really don't understand the level of self entitlement that cyclists seem to have and why they seem to have such a shitty attitude towards drivers and pedestrians alike. A bicycle rolling through a stop sign isn't any less dangerous than a car rolling through one, if anything a car is easier to spot than a bicycle and cars don't tend to have their visibility shuttered by driving between full lanes.
The reason why most countries do not allow roll through stop signs or at least heavily restrict them is that rolling through a stop sign sets the wrong behaviour pattern because once you get used to a stop sign you know you can roll over you aren't going to slow down to roll over speed you might simply slow down by a bit but not nearly enough to respond appropriately.
The same thing is going to happen to cyclists they'll get use to it and eventually get careless they won't give 2 ducks about the padestrians trying to cross the road with already ludicrously short light times and they'll take more and more risks as far as crossing the intersection goes.
Cyclists don't have mandatory insurance, they can hit anyone and do pretty hefty damage if it's at speed and good luck suing them for anything at least with cars in most countries you can always sue the insurance of the offending driver. Heck at this point I'm not even entirely sure if being hit by a bicycle in the UK constitutes a "road accident" so they might as well just take off and not give a flying duck about it, it happened to me got hit in the side I assume by the stem/handlebars at pretty high speed the cyclist didn't seem to give a shit at all and just wobbled a bit and continued on his way without even checking. It was a sharp pain but not bad enough however the night after half my side was purple if it would be a bit stronger or sharper hit I might've ended up pissing blood for 2 weeks.