I don't think you're making a very compelling justification for bicycling on sidewalks.

Your statistic regarding UK pedestrians being killed/hit vs bicyclists being killed/hit isn't strong as it's probable that nowhere near as many bicyclists choose to ride on the sidewalk as compared to staying in bike lanes and roads. That is, if more bicyclists opted to ride on sidewalks, the incident rate would certainly increase.

Additionally, rationalizing this in terms of the risk towards the bicyclist just comes off as selfish: "I'm not comfortable with the risk I'm facing while bicycling on the roads, therefore I will put pedestrians at risk instead."

Perhaps instead of endangering pedestrians, something more constructive would be to engage politically to improve the situation (maybe you do this already, if so, awesome!).

In south Australia its legal to ride a bike on the sidewalk and every time I have seen someone do it they have done it safely and respectfully. There are some streets that are just too dangerous to ride on and hardly anyone ever walks on the sidewalk.

In some ways civil disobedience is a form of political speech.

That's why you specifically need physically protected bike lanes. Painted bike lanes are nearly worthless.

Nobody would accept having "painted walk lanes" instead of sidewalks, but for some reason this is considered an acceptable norm for bikes.

Even worse in places like SF or also frequently becomes the turn lane for cars at the end of the block resulting in everyone being upset.

Are they better than nothing, which is what was there before?

Marginally. They do help some cyclists, and they reserve space for future, better bike lanes. On the other hand, they're inefficient because most people rightfully determine they're unsafe and won't use them, which gives ammo to anti-bike crusaders.