I dunno shit about math or statistics but it seems against common sense that of all the stars out there and inconceivable distances that there aren't other 'intelligent' species. Some are still in their respective stone age, some have evolved to the point of being conscious gaseous clouds, some are insects or prairie dogs with hive minds.
Regarding the rigors of space travel, thats all assuming that how a lifespan is measured on earth is comparable any place else or we are talking about carbon based life anyways. We think living to be 100 is long. Maybe for whatever transuniversal alien race we are theorizings, their life spans are 1000 of years. Maybe they got so far in genetic engineering they don't look or function biologically any of the ways they used to or any of the ways we think of.
I dunno, but to me it just seems unlikely we are anything special or an anomaly among an infinite otherwise lifeless universe. And as far as the reports and sightings go, imagine a primitive warlike species in star wars that hasn't developed intergalactic travel yet but has engineered superbugs and nuclear weapons... If I traveled the stars to get to this zoo, Im not going to show those shaved apes my whole hand. Better to observe, record and report and mess with their heads a bit.
I feel apprehension to the notion of a universe with non-human life derives from the human condition of "sapien exceptionalism". We love to think we are amazing and belittle creeping ideas that undermine that foundation. Our 'minds' are probably the most fragile part of us.