Good Question. Like all races on Planet Earth, there are good and not so good people within each race. Perhaps it is safe to assume the same for our off-world friends also.
At least from what the ET's have said, there are some ET races that hold high respect for human beings, whereas there are others that perhaps could not care less about humans, that we are lab rats for their clandestine tasks, and see us as a nutritional source. (yes meaning they eat us!)
But of course, it may be erroneous to pass judgement on some particular ET's races, for in their eyes, what they may be doing would be seen as positive and a benefit to all involved.
Encounters happen in all sorts of various ways. Because encounters with ET's are not understood, the encounters can be terrifying. If a human has experienced a very traumatic encounter with ET's and taken against their own free will, being subject to certain intrusive experiments and being rendered helpless to defend themselves, one would quickly conclude this is a very negative experience.
The Kelly Cahill Encounter
On the other hand however, the ET's may conclude that what they are doing is in the best interest for the human... Furthermore, ET's are quick to add that in many instances, an agreement has been made between the human and the ET's, and that the human would WILLINGLY partake in these encounters.
They may even go as far as to say that the human is apart of them, comes from THEIR DNA and that they aided in their creation.