Just remember billions of planets and solar systems exist. In 1988/89 I don't believe that was anywhere close to mainstream thinking or belief. Think about that now and that seems totally dumb/ignorant we didn't already believe that.
Also, you have to keep in mind the testimony/interviews with the military pilots. They know that what they saw was nothing they have seen before or of any kind of conventional technology and movements the human body cannot withstand with tech we know of. Someone has it and it came from somewhere. Again just hope it is the good guys.
If they are visitors, I think they must be on the side of good, or at the very least neutral observers. If they wanted to take us over, they could do it without breaking a sweat given the technology they must possess to enable interstellar travel.
I think they would be here to keep us from blowing ourselves up. They want our species to continue its progression.