No surprise makes more sense than you do...<quoted text>
Let's break that down a bit.
Man has not discovered signs of life on another planet. Check.
Does this mean that life on other planets do not exist. No.
Now let's consider the range which Man has the ability to observe in regard to the Universe.
Say Earth was a single grain of sand on a vast beach. Now let's say you dropped a dime on that beach, over the grain representing Earth. THAT is how much we can observe, and very limited observation at that. With this in mind, can you honestly believe that based solely on our observations, there is no other life forms in the Universe? Are you that simple minded?
...regarding the likelihood of there being life anywhere else in the universe; he/she just doesn't know "why".