Seriously, there's a bike lane right there

Horn, universal.

And unnecessary. Cyclists don't need it to know that you're there, and you're not warning them of any danger about to befall them (unless that's you, but really, that puts you firmly in the wrong as a driver).

bad car drivers are far fewer than cyclists in regards to predictability on a percentage basis.

They present a visible minority on the road, to be sure, but are they more of a danger than a speeding motorist in a poorly maintained vehicle? Are they more or less likely to be lulled into a false sense of security because they are inside? After all, as you put it

I'm buckled in with a seat belt in a two plus ton vehicle with crush zones and airbags

Furthermore,

Shouldn't the one more at risk care more than the other about its own safety ?

Absolutely not. You are the one in the multi-tonne vehicle, and it's your responsibility to be driving it safely, taking care of others. If a kid wanders out into the road, if a driver hits it it's going to be the motorist at fault. Just as the driver who collides with the rear end of another car, it's always the car which is driving behind that is culpable, since it's always avoidable - even if the car ahead is driving like an idiot, slamming the brakes on, the driver behind should be in a position to stop before rear ending the car it is following.

You have a duty to be aware of your surroundings, and driving, while it has become a 'safe' pursuit is anything but. Your vision is impaired driving at anything over 20mph ( you develop functional blind spots), and your reaction times are effectively slowed by the fact you're driving faster than most anything around you (trees, cars, pedestrians, cyclists, etc). A cyclist should be cycling with the correct safety gear and in a safe manner, but even if they do that, they are still more at risk than you will ever be in a car.

I'm one hell of a paranoid when I ride a bike nowadays.

Good. It's the safest way to be on the road. Drive that way too; total awareness of your surroundings is the only responsible attitude when in charge of a vehicle, however it's powered and however many wheels it's got.

I'm not excusing bad cyclists, or those endangering themselves (and putting motorists at risk psychologically should any fatal accidents occur to the cyclists), but the onus will still be on other road users to act appropriately around them; either by acting with caution rather than aggression (giving ample room to overtake a wobbly cyclist, for example) or by simply adjusting their driving (ie, going slower), because the fact is even if they're in the wrong, if they get harmed by a driver they will always come out worse off.

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