Porque ele é um observador ou trabalha para eles. Provavelmente Uatu, o observador designado para observar a Terra. Confirmado pela Marvel nos Guardiões da Galáxia Vol 2. E tenha em mente que as séries da Netflix são parte do MCU.
Marvel chief Kevin Feige has endorsed the popular fan theory that Stan Lee is playing the same character in all of his MCU roles. http://screenrant.com/stan-lee-mcu-cameo-theory-marvel-kevin-feige/
“Yes, we always thought it would be fun. Stan Lee clearly exists, you know, above and apart from the reality of all the films. So the notion that he could be sitting there on a cosmic pit stop during the jump gate sequence in Guardians was something very fun – James had that idea and we shot that cameo and loved it so much, you know, you see it a couple of times in the movie. It wasn’t in for a long time and we put it back in towards the end of the process where he references that time he was a Federal Express agent – we thought it would be fun to put that in there because that really says, so wait a minute, he’s this same character who’s popped up in all these films.”