You overestimate the difference between an interstellar civilization and us. Not only are we mere centuries to millennia away from that level (as opposed to millions of years), we have already reached the threshold of reason. The difference is more like cavemen to us, and cavemen and of course cave-babies could be integrated into our society, as long as they are educated beforehand.
Plus, their education method (of the interstellar civilization) are probably very advanced, making it even easier.
Plus, their education method (of the interstellar civilization) are probably very advanced, making it even easier.