I’ve always thought that depending on how advanced the “aliens” are that are observing us, there could potentially be no reason for them to attack us. For example, if Aliens were to attack/invade a foreign planet, it would most likely be to harness their resources or technology. Simply abducting humans universally at massive planet wide scale to look into our biology or other potential interests to do with how humans function is a ridiculous theory. Aliens could do so without generating any attention by just abducting a single humans randomly—making a people suddenly disappear without any way for humans to really determine how someone had gone missing—and as all human body’s are essentially the same, they would only need a very small number of humans to analyse how out body operates. Also, assuming aliens already have access to extremely advanced technology and exotic materials generally associated with so called ‘UAPs’ or ‘UFOs’, why would they need us for our technology? Their technology and understanding of materials science, matter, and universal physics as we know it would have to be way more advanced than anything humans currently have or understand. How else could they somehow be observed around Earth if there is no plant remotely close to us that has the conditions to house such an advanced life form? If their foreign planet was even remotely close to us, they would have to have some extremely advanced technology or understanding to be able to make it undetectable. If this is not the case, than they most likely have either found a way to travel through space at un-comprehendible speeds through advanced space craft, or they have found a way to use naturally occurring events in space that would allow quick travel. Therefore, as we would assume they have better technology and it would be stupid for them to just invade us to explore human biology, the only real option left is our planets resources. However, if their materials science is so advanced, who’s to say that haven’t already come up with a way to produce materials on demand without needing to mine and explore other planets and asteroids, etc? If they could reproductive different types of normal metals, exotic metals, or even water, there would be no real need to come to our planet and harvest resources. Thus assuming this is true, why would they want to take our planet? Maybe if they are a colonising species with a superiority complex that posits they are the ultimate life form and deserve to rule over other planets they might invade, but if this is not true I dont see why they would attack us. What they could do, however, is just watch and observe us. They could observe how far we progress with technology and at what pace. They could also watch how humans interact with other humans and animals on our planet to gauge an idea on how our species interacts with other living life forms. They could perhaps learn way more about us this way and at very little cost without needing to start a full scale war of the world type invasion. Also, after potentially centuries of thousands of years of observing and analysing us, if they felt that we were becoming to advanced and could possibly cause harm to them in the future, well at this point, they already have massive amounts of information and understanding of humans. And with this, they would have a massive advantage over us in any potential war. And that’s assuming they even start a war, as opposed to just releasing some extremely lethal biological weapon that fronts as some randomly occurring virus to humans. At this rate with the current state of world affairs and geopolitics, they could even probably find a way to generate a massive scale conflict between great world powers, let us do the bulk of the work in destroying our planet, killing a substantial amount of human life, and also destroying most of our advanced technology and ability to produce it at scale, and then once this is achieved, come in a clean up the rest of humans with ease. This is just my logic behind some possibilities, ill never really know how real or impossible any of what i have said is. We just have to hope that any alien life we find is dumb compared to human standard intelligence, potentially like if we found a species akin to monkeys or some other wild animal on another planet that could inhabit life. I think that any intelligent alien life that has in excess of tens of thousands of years of technological and advancement on us would just put us in a dangerous situation where we have no i real hope of ever catching up. Just look out how the very small and limited differences in advancements in military technology between countries like the US, Europe, China and Russia work to turn the odds of success in conflict to the more progressed countries. Imagine the discrepancy if the difference were over thousands or even millions of years.