I'm not sure specifically which 'old man stalker story' you are referring to. It could be about an old man who stalks someone for various reasons like revenge, obsession, or misunderstanding. Maybe he's stalking a younger person in the neighborhood or someone he used to know.
One common theme could be obsession. The old man might be obsessed with the person he stalks, whether it's for love in a warped sense or some other strong emotion.
Perhaps it's a neighbor who has some sort of mental illness. They might have developed an obsession with the main character for no clear reason. They see the person through the window and start to stalk them, seeing them as an object of their strange fixation. Another possibility is that it's a criminal who has randomly chosen the house to target. They might be casing the place for a robbery, but their presence in the window makes them seem more like a stalker.
Since we don't have much information about this specific 'blackkklansman old man story', it's difficult to say who the old man is. He could be a fictional character created to represent the older generation's experience with the KKK - related events in a story based on 'BlacKkKlansman'.
In 'the old man at the bridge story', the old man is an ordinary person whose life has been upended by war. He seems to be a bit forlorn and lost. He has his own little world back home with his animals, but now that world has been destroyed by the war. He is at the bridge, a sort of liminal space between the past and an uncertain future. He represents the countless individuals who are displaced and left in a state of confusion and despair during times of war.
There's not enough detail to know for sure who the old man is. He could be a variety of things. He might be a war veteran who has some skills or knowledge that comes into play in the story. Or perhaps he's an old family friend of one of the characters, and his presence in the story is to provide a different perspective or a connection to a past event that is related to the events in 'Equalizer 2'.
He is a character who embodies the despair and displacement brought about by war. He's an old man who has been through a lot. Maybe he had a simple life before the war, but now all he has left is the bridge where he sits. He doesn't seem to have any strength or motivation to move forward, and his presence at the bridge is like a statement about the state of so many people during war.