Well, there are a number of different physical types reported, but the "greys" have been seen a fair bit. Others have reportedly been seen who look so much like us Earth people that no one would know the difference if they were dressed in a conventional manner, and some of those may already be living quietly among us as observers.

They do seem to be waiting for something. It could be:

1. for us to stop being so warlike and paranoid
2. for us to establish a unified World society so that they have someone they can actually talk to here that represents the whole human race in a real manner
3. for us to stop trying to shoot them down with our archaic military junk
4. for us to give up atomic weapons and other crazy stuff like that
5. for us to welcome them in an open fashion instead of covering it up
6. for a looming ecological catastrophe to sort itself out, after which the situation would be radically different
7. or a hundred other possible reasons...

Or maybe...

They do just see us as "pets" or interesting creatures, but not advanced enough to bother having diplomatic relations with.

Or a hundred other possible scenarios.

I can just imagine a bunch of monkeys trying to decide what the weird aliens (humans, I mean) in the airplanes and bulldozers are up to, and why! :-) I'm sure they would be quite offended to discover that our interest in their forestland is not entirely because we are fascinated with monkeys and desperate to get to know them.

I mean, hell, monkeys would probably figure the Universe revolves around their concerns too....just the same as people do. They would not wish to be seen as creatures of little importance in the grander scheme.

Do the guys in the airplanes care what the monkeys think when they fly over? No. Do all the monkeys believe there are guys in planes up there? No. But there are.

Consider the possibility that we humans may be so culturally backward by the visitors' standards that they cannot even conceive of successfully relating to us at this point, due to problems in communication and mutual understanding. It's entirely possible. And if so, it would scare the hell out of our military and our politicians and they would keep it a secret if at all possible. They would not want to admit to something that is totally beyond their control. What else have they got except the illusion of control standing between their present position of authority and a total loss of prestige and public confidence that would follow such admissions of helplessness in the face of an alien presence?