So it again begs the question..why? If they have the technology to completely mask their presence and travel the stars unobserved..why the hell are they here watching us?
You can write a whole book about it but i'll kick the door straight away.
They are watching us because they are in a way our creators atleast according to Sumerian texts. The Sumerian texts was written in a language that was developed in ancient Mesopotamia and is the oldest known written language originated around 8000 BC.
They called them the ''the engineers'' ore sky gods other civilisations called them star/cloud people ore gods, giants and angels. (They are the ones who build all those megalithic structures) Those Engineers seeded life on thousands of planets and have looked to learn about how life evolves in different ways including Earth in the hope that we too might one day reach their vast intellect to understand the universe to unlock the secrets of space travel and the after life and who we really are. They say that we are made from flesh and blood but our soul is made from pure energy.
They will return one day when we're are ready.