"an instance of involuntary urination or defecation in one's clothing
can't argue with that"
That's what nappies are for. It's a reasonably foreseeable risk especially if you've been near children, junk food outlets, animals or other humans who've been breathing or perhaps sneezing. If you crap your pants it's your own fault if it ruins your day. You might not have been able to stop it, although with planning you can avoid most of those things, but you could have taken reasonable steps to mitigate the risk that soiling yourself would lead to a smelly, wet mess that would be publicly humiliating. The simple precaution of wearing a discrete but effective nappy could avoid the worst effects.
If we are to pursue this line we have to accept that in every circumstance all possibilities are reasonably foreseeable and steps can be taken to avoid those possibilities or at least to minimise their impact. Everyone is at least partially responsible for every ill that befalls them. The pedestrian's death could have been avoided if they had anticipated the possibility of the driver mounting the pavement and stayed at home. The child's death is partly their own fault - they are old enough to have had basic road safety training but they failed to listen and properly absorb it. They failed to implement it and instead allowed their attention to be distracted by the friend shouting from the other side of the street. It's partly their parents' fault. They gave birth to them in the first place, failing to properly consider all the stupid things they might do, then they failed to teach them proper road sense before allowing them onto the street. They then failed to supervise from a reasonable distance, far enough to give the illusion of independence but near enough that they could rush forward and save their child's life. Idiots.
The cyclist brought it all upon themselves. They cycled on the road for one thing. The possibility of being killed is easily anticipated and readily avoided. They could have had more lights. They should have made themselves more visible. Although cycle helmets offer a little protection, they could have worn a downhill helmet or a motorcycle helmet, anticipating the possibility that a car might drive straight into the back of them. Body armour could have helped.
Dear Lord, I feel sorry for the motorists.