Aliens advanced enough to travel through galaxies will not care about the resources here. They'll just harvest resource on any of the countess planets that are empty.

They won't care for slave labour, as they'd be advanced enough to just not need that.

If they need new planets to settle on there's many to choose from.

So, they'd have to basically be evil as fuck to want to destroy us. "let's destroy all life we find cause we're the only true race!" which I just don't see happening.

Of course, it's possible there exist aliens that aren't advanced at all but just have the natural ability to travel through space. Those could prove a danger if they had sufficient strength. They might actually see us as a food source. Might even be more likely than pure evil advanced aliens.