[..] I'm not sure why it would be assumed that any being capable of reaching us would be hostile.
The post you're replying to didn't contain that assumption.
As opposed to merely curious or even entirely disinterested in us. We wouldn't be special. We wouldn't be important.
So you agree with the "theory" in the post you're replying to, namely that these hypothetical aliens likely wouldn't be our friends.
We might or might not be special to these hypothetical aliens. We have no idea how common life is or how common complex life is or how common sentient life is or how many civilisations at our level of development exist at this moment in time. We also have no idea about the motivations of these hypothetical aliens. Maybe we'd be interesting to them. Maybe very much so. Maybe we'd be the only civilisation at this level of development that they've encountered so far. That would make us a unique opportunity for study. That would probably be the case anyway - even if there are lots of planets with life, even sentient life at the same level of development, they wouldn't be exactly the same as on Earth.
I know in all the movies they have to conquer the Earth because they want to make it their new home, but in reality if they have the tech to zip around the universe they probably couldn't give a crap about this particular planet, or even galaxy.
The only scenario I can think of that would be different from that is if there's some lifeform on Earth that's valuable to these hypothetical aliens. Could be anything. Maybe tulips are all the rage in fashionable circles amongst them. Maybe the bark of some kind of tree contains a chemical they can use to cure some disease present amongst them. Maybe. Who knows?
[..]Some people think they will be hostile because that's what humans would do in our current state and this goes back in history as were are not (globally) as intelligent a we need to be to have that kind of capability, we are still primitive. If a species is hostile with that kind of capability then they will almost certainly have destroyed themselves. Picture the scenario, factions of a civilisation at war, with UNLIMITED power and energy at their disposal, it only ends one way. The reason I say unlimited is because you have to have unlimited power to generate the kind of forces needed to uphold folding space-time to flick one one place to another in the universe (technically not physically travelling faster than light but effectively using wormhole theory which on paper is valid but as said, you need unimaginable energy rivalling that of black holes iirc).
Those civilisations won't be hostile, they will be scientific explorers in nature with no intention to interfere but monitor and maybe make contact when the life they are monitoring has evolved beyond a certain point. I can't see it being any other way really.
I can. Here's a few:
1) They're not hostile to us. They wouldn't need to be hostile to us for them to be devastating to us. The absurd difference in levels of knowledge and power would be enough for that, but if they're more intelligent than humans (as you believe they are) then we're screwed. The best we could hope for would be for humanity to quietly fade away from being pointless while the aliens do their best to make life pleasant in our little wildlife park.
2) They don't have unlimited power and energy. You'd need unlimited power to do rapid interstellar travel
with current human knowledge. So it's impossible with current human knowledge. So if these hypothetical aliens could do it, they would have to have other knowledge. So maybe they know how to do it with much less power.
3) They have factions hostile to each other but haven't destroyed themselves
because they have so much destructive power that a full on war would destroy all the factions. The same as humans with nukes - Mutually Assured Destruction - just scaled up somewhat.
4) They don't have factions hostile to each other because they unified through a form of nationalism with the nation expanding to the whole species. In that scenario, they wouldn't be hostile to each other but they would be hostile to outsiders.
5) They have concluded that humanity poses a potential threat to them in the future and should be destroyed now, before humanity becomes that threat to them.
Those are just off the top of my head. There are probably other possible alternatives to the "aliens as benevolent gods of peace" scenario.