You are right, I am confused. How would I keep track of someone if I don't know them? This includes not just people but all of the animals that I interact with. My mom used to have a bird feeder and I spent countless hours watching the birds. I got to know several dozen as individuals, I was aware of their injuries and their style of eating (timid, brave, quick, slow). How might I keep track of them without knowing them? Perhaps you might consider that your ideas on this subject are a bit muddy?

Also, you misread the original comment when they wrote "their whole lives" -- they are asserting people never know more than that 30 to 100 people, an assertion which is absurd.