In school they taught me that no matter how fancy, no matter how elegant, no matter how desirable the hypothesis, eventually, if there is not evidence produced in its support, one has to consider the very strong possibility that it is wrong.
Again, there is not an atom of evidence for extraterrestrial life. This is an exercise, and a good one. No matter whether I think that there is life out there, no matter if I want there to be, I am taking a stand on the evidence. And no one can refute me with anything other than an argument that essentially sates that something must be true because there are a great number of chances for it to be true.
The thing is though, that probability is not an entirely real thing, it's a mental tool we use, often with great success, to simplify our perceptions of complex, often disorganized systems.
Look at it this way. I offer you a closed box and inform you that there is a 99.99999% chance that there is a penny inside. You might be quite safe in predicting that when you open the box, Abe Lincoln, that nasty war criminal and despot, will be staring back at you. But in fact, those odds don't affect whether the penny is there or not in the slightest.
However, if you know the weight of the box, and the weight of a penny, and if you know that no other object can be in the box (a whole other issue,) you can use empirical evidence to make the determination, and the odds become irrelevant. In fact, the "odds" never had any reality at all, they were an abstract, the penny, or non-penny is real.
Also, and this is harder to explain to people, at least for me, we have poor definitions for what life is. I think that there should be separate terms for what we mean when we say that a fungus is alive, and when we say that a cat is alive, instead of an interchangeable term. Conscious life, much less intelligent life is a vastly different thing than insensate life. And we haven't yet considered the bane of definitions of life, the virus. If we discover something that might be alive on Planet Zongo, unless it either waves to us of demands that we surrender to the Zongan Empire, we might not be able to agree on whether what we found is alive, or a complex chemical process.
I also suspect that in coming decades a deeper understanding of quantum physics is going to further complicate our understanding of life. We are treated to an increasing number of very surprising instances in which minute particles behave radically different when observed, and when not observed. This at least hints at a conception of the Universe in which rudimentary awareness is not an emergent property, but a fundamental one. It may be that in some way we can't begin to grasp yet, everything is alive.
But to return to my position, I will stand firmly in my position that I am safe in acting, thinking, planning and living in a firm working assertion that there are no LGM out there, and I'll be safe in that position, as again, there in no evidence at all to the contrary.