According to the interview, the Director speculates on what the Alien Entities, Beings or Creatures could or would be like. If I understand correctly the above, Director <PERSON> does not say "this is what they were", so it may remain (deliberately?) vague. You decide.
If this, however, would not be the case, the most plausible possibilities could be one of the following:
1) An advanced Alien Civilization, Mind, Entity, Being(s), or Creatures(s) created the Artificial Super Intelligence {ASI}, and sent it out into Interstellar Space to explore.
2) Same as 1), but the ASI evolved on its own, and started to conquer, exploit, and exterminate civilizations -- maybe it considered other life forms so low, like ants to us, that killing them was akin for us to step on a bug, or getting a haircut without worring much about the hair (lower life form) discarded -- in order to pursue its own goal and to survive.
3) An Alien Species nearing its own extinction creates an ASI that stores and preserves its culture in digital banks, and sends it out as a last testimony and preservation of their culture and knowledge. The ASI is given free reins to evolve and behave as it wishes.
4) An Alien Race creates an ASI that exterminates its own creator and goes on an expansion and killing spree in this Universe.
5) TET is created by an Alien Civilization to rid the Galaxy -- perhaps the entire Universe -- of other Civilizations that could be a threat to itself. 44
Sort of a 'Predator Artificial Intelligence' going on a search and destroy mission.
Some of these possibilities can be found among solutions for the Fermi Paradox. Many other scenarios are plausible, Director <PERSON>'s and the Scientists' consensus are of course very high on the list.
However, a sufficiently advanced Civilization, especially one capable of creating an ASI like TET, should be able to find ways of Superluminal or FTL {Faster Than Light} travel, like wormholes, using Time Dilation, etc. The Directors explanation may not be the only one, simply based on Human knowledge and (limited) understanding of this Universe and the Cosmos.
Thank you.
<PERSON> -Author & Writer if Science Fiction -Human Ambassador on planet Earth for The Jovian Collective, a.k.a. TJC or ONE - Organism Near Earth 45