In theory, you'd expect conservatives to react with fear and hostility, while liberals would be more likely to welcome the aliens. For an empirical reference point, look at how conservatives and liberals react to human "aliens" who immigrate to their countries. It should be noted, in fairness, that the conservative reaction would be the appropriate one if it turned out to be like "Independence Day" and the aliens were actually here to conquer us.
I think your's is the correct prediction regarding aliens, but it demonstrates that ideology is a negative in interpreting such events.
This is my perspective which fits none of the above.
First, this would be absolutely fascinating from a scientific perspective. We have wondered for countless thousands of years if others beyond our world exist, be they physical or spiritual, and this would answer the first part. It would also increase the universe of intelligent life from a data point of exactly one. Well it does more scientifically than I can imagine. It would address societal development, that intelligence exists and can lead to a technological mindset and on and on. It also potentially increases our scientific knowledge by giving us clues as to what is possible in the real world and provides the potential opportunity for new avenues of research. We now know that live more advanced than us exists. That's the positive.
The negative is that we know that life more advanced than us exists. Where there are two technologically species there may be many more. Physical laws being the same, every organism must have the ability to survive hostile environments. All resources are limited and so will develop the ability to compete. In our case and that of planet "X" this lead to intelligence and potential ability to expand beyond planetary boundaries. In all cases, survival is THE biological imperative exists simply because unsuccessful organisms always die.
That last sentence is the key to concerns. We cannot assume any like moral characteristics or even sentience as we understand it. Now back to survival and resources it make sense at some level of development that thermodynamically it is advantageous to visit and take resources from off-world. By that I mean that entropy and energy are key to survival. If less disorder and resources are to be had by taking them elsewhere then it is reasonable to assume it will happen. Human morality or the equivalent may not exist at all. It might, but the balance life and death might be determined on that.
Which if the three scenarios, indifference, benign interest or hostile intent would be true?
I have no idea, I can have no idea and therefore I can have no overall opinion on what things mean. Given that being "good" doesn't mean accidental damage to us or our world is a forbidden possibility, and that self interest of survival by one vastly superior species likely means extinction, I would err on the side of caution.
As a physicist once said in response to the question "What should we do if aliens call"?
"Don't answer!"
I agree that caution needs to be foremost, but that is determined not by who I support or fear but what I believe to be a rational analysis of possible consequences given what we can now know.
Ideologies would not help where they create a bias one way or another.