If there are other intelligent beings in the universe, then why aren't they here?
First of all, I have to question the use of the word "other". Are you suggesting that there are intelligent beings on Earth? I assume you're referring to humans.
That having been said, okay, pretend there are other "intelligent" beings out there, same intelligence as humans. Why haven't they come here? Why haven't we gone there? We're the same intelligence as them, right?
The correct question would be "if there are much more intelligent beings in the universe, then why aren't they here?" The answer is because their first contact with us was an intercepted transmission of the Jerry Springer Show.
Intelligence, as we think of it, is a very narrow spectrum. Extraterrestrials would think completely differently from us (I am Spock had some insights from a SETI scientist on this). Math is not a social construct in that 1+1=2 &c, but life on other planets would think this in a completely different manner, completely undecypherable by humans.
While we're at it, what we consider life is a very narrow spectrum. In the Star Trek episode 'Devil in the Dark' they discovered Horta, which is a silicon based lifeform. Bones, of course, instantly argues with that analyses "That's impossible!" After all, we've never seen a lifeform like that, so it can't exist.
Or maybe they're hugely advanced but have never been enticed by that big void filled with little glowing white things. Maybe they're just interested in neurobiology, genetics, and philosophy. and mathematics.
Define intelligent. Define life.