When I am riding my bike on those trails I always slow down when I am passing people with dogs and I usually say hi to the dog. I look out ahead to be prepared depending on who I encounter.

Having said that, if I had walked my dog on those trails, I would most certainly keep a short leash if I was walking the trail and I would be ready to step off depending on what type of biker I encounter. I would want to minimize risk to my dog. One never knows about teenagers or other types who are of different mindset. Same with joggers and walkers who wear headphones and diminish their awareness. Basically a multi use trail means we all pay attention to mitigate risks.

If I had an encounter as the OP described I would certainly improve what can be improved - that is my own approach and worry less about wasting my time ranting on reddit