2nd party is unpredictable. You can reduce risk by avoiding traffic and choosing routes with fewer intersections. Other than that, 2nd party risk control comes down to alertness and riding with big gaps around you. Someone here called it a bubble. There are distracted idiots everywhere! Keep your distance.
3rd party "critters" are also unpredictable but there are times and places with higher and lower risks of encountering them. Riding at dusk thru wooded areas during the deer rutting season is high risk.
All sports are risky, but ours needn't be as bad as many riders may
I somewhat agree and disagree on these statements, so here's an alternative point of view.
#2 as someone with 20+ years of experience commuting in worse gridlock in the country and clocking 500 commuter miles a week I can say that 80-90℅ of drivers are predictable, and those who are not or just plain f-ing crazy are usually easy enough to put the distance from. What usually gets you that they don't see you, and you need to assume that they won't. So if I am coming by the car which has a chance to change into my lane, I give it no chance. I position bike on outside and cover horn button. Have headlight modulator and airhorns, last time I used it dude sh!t in his pants and jumped to the shoulder; thought 18-wheeler coming through.
There's also a body language, they hit the brakes and cage becomes twitchy when someone is looking at the mirror.
And you usually have a choice of the route to minimize risks.
With regards to #3 I would not classify it as animals, just external conditions. Rain, gravel, leaves, falling rocks and trees are all there along with animals. And even with animals they have specific feed times, so they are not out 24hr. And they're more likely to be in some spots than others. So while it is never 100℅ in your control it is never 100℅ out of your control either.
So being at 2am on Pennsylvania turnpike with construction in heavy downpour on bold tires, 2up loaded is not wise choice; I am glad I lived to tell the story.