Hmmm.. Seems pretty clear what is going on.
1. The devices have been here for a long time, observing. At this point, they would know about each of us individually, easily mapping things over time, predicting our actions with uncanny accuracy and avoiding detection whenever necessary.
2. In the past they didn't build monumental architecture for us or give us any technologies. We may not even know what is of particular interest about us for the phenomenon. Imagine a very advanced sentient drone, an observation and communication device; not the Star Trek ideas of folks like deGrasse Tyson who wants to have dinner with an alien. Many scientists assume aliens would arrive with great fanfare in a great ship with light sails! Not.
3. It seems the interest the phenomenon has in us is pure curiosity; we may be the only advanced biological life they have encountered or know how to get to.
4. There are waves of UFO visitations; these seem to occur during stages of technological development or upheaval, e.g. "airships" during industrialization, foo fighters etc. during wars.
5. Imagine you lived on a different plane of information universe and could see the connections between events and objects far beyond what puny humans are capable of; like the scientist looking down on the rats in the maze.