Adymus
`dagon
Who would better understand the flavour of an orange? One who actually eats them, or one who watches others eat them?
That is a rather misleading comparison.
While the one who eats the orange will understand how they respond to the flavor of the orange, the one who watches others eat will understand how others respond to the flavor.
But knowledge is valuable.
I don't think that they would understand better how the person reacted to the orange. It's the difference between primary and secondary sources.
Anyway, I think the word "stalker" is being taken out of context here, because it's supposed to have a negative connotation to it. It's used for someone who does this type of behaviour to the point of harassing the person they are stalking.
Social observation is useful, of course. Writers are known for doing it to the point of losing their own social interactions. Looking through people's diaries, FB accounts and that sort of thing is usually just described as being nosey. Nothing weird. Nothing special.
And I won't just ignore the very first thing I am given to read about a topic. Of course I'm going to bring it up.