We don't have a complete theory of abiogenesis, true. But we don't need it to see that our plausible hypotheses don't make life arising to be that unlikely. And we have empirical evidence as well: we have traces of life that date back to very soon after Earth became hospitable. The Late Heavy Bombardment http://en.wikipedia.org/wiki/Late_Heavy_Bombardment ended some 3.8 billion years ago. The oldest fossils date to around 3.5 billion years ago. See http://www.paleosoc.org/Oldest_Fossil.pdf This suggests that life can arise in under 300 million years. It is possible of course that life arose during the LHB, and we cannot rule out panspermia. But together with the fact that many of the basic chemicals (e.g. many amino acid) used in life are not much more complicated than those that occur through non-living processes, we shouldn't at all expect there to be some magic time period it takes before life can form.
As to your statement that "primordial soup experiment was bullshit"- I presume you are taking about the Miller-Urey experiments http://en.wikipedia.org/wiki/Miller-Urey_experiment. Why don't I just quote from the introduction of that Wikipedia article.
After Miller's death in 2007, scientists examining sealed vials preserved from the original experiments were able to show that there were actually well over 20 different amino acids produced in Miller's original experiments. That is considerably more than what Miller originally reported, and more than the 20 that naturally occur in life. Moreover, some evidence suggests that Earth's original atmosphere might have had a different composition from the gas used in the Miller–Urey experiment. There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide (CO2), nitrogen (N2), hydrogen sulfide (H2S), and sulfur dioxide (SO2) into the atmosphere. Experiments using these gases in addition to the ones in the original Miller–Urey experiment have produced more diverse molecules.
You may want to look at the section "Other experiments http://en.wikipedia.org/wiki/Miller-Urey_experiment#Other_experiments. So, yes by all means, please point me and others where to go to read up on how Milley's work was "bullshit" since I don't see it in any of the obvious places.
, it's just not possible to build the kind of things you'd see at stellar distances.
I'm curious why you think that given that for example a small Class A stellar engine https://en.wikipedia.org/wiki/Stellar_engine appears to be buildable with what we know about materials science. And this isn't the only example of such. The requirements are purely on the amount of resources that need to go in, not physical limitations. Yes, some specific suggestions would require materials that look impossible. For example, an inflexible single piece ringworld is likely to be impossible (the tensile strength among other requirements make it implausible). But many megascale structures aren't in that category.
But let me guess, you believe the aliens use magical particles like tachyons and gravitons to communicate and we're just too stupid to figure it out but when we do we'll be invited to the galactic fraternity, right?
No. Absolutely not. First note that tachyons and gravitons aren't "magical" there's a massive difference between theoretical particles consistent with the laws of physics. It is likely that tachyons do not exist, since they'd either allow causality violations (unlikely) or they'd not allow communication. Similarly, thinking that one could use something like gravitons to communicate is just silly since they'd be incredibly weak. I don't have any belief in some galactic fraternity, but your attempt to pigeon hole rather than read what people write is interesting. Concerns about the Great Filter arise specifically from there being no evidence of anything remotely like that. If there were any reason to think that was at all likely, we could breath a lot easier.
For the record I think that there is life everywhere in the universe because the laws of physics will be the same.
So, we're in complete agreement here. But the problem is what this leads to: it means that out of the civilizations, none of them are trying anything on a large scale, not even the few more ambitious ones. This suggests that once life gets sufficiently advanced, it gets wiped out somehow. The Great Filter is a serious problem: Nick Bostrom and his colleagues at the Future of Humanity Institute for example have given this a lot of thought. See for example http://www.nickbostrom.com/extraterrestrial.pdf. And this is very much the sort of problem where if it exists, pretending it doesn't won't make it go away.
This is pretty scary. One of the major unsolved problems right now is the Fermi problem- why we don't see any signs of civilizations other than our own, not just no radio transmissions but no Dyson spheres (and yes, we've looked http://home.fnal.gov/~carrigan/infrared_astronomy/Fermilab_search.htm, stellar uplifting, ringworlds or the like. Whatever is blocking this is the so-called Great Filter https://en.wikipedia.org/wiki/Great_Filter. Now, some of the Filter could be in our past. It may be tough for life to arise or for multicellular life to arise, etc. However, the more disturbing possibility is that it exists in our future: maybe civilizations before they can spread out manage to wipe themselves out with their technologies, such as through nuclear war, bad nanotech, engineered bioweapons, resource depletion, environmental damage, or something we haven't even thought about before.
Over the last few years, more and more evidence has suggested that a lot of the obvious filtration events in the past aren't serious filters. For example, we've found that planets are common. This is not only an example of more such evidence, but it suggests that if life got started it would have had billions years more to evolve, meaning that evolutionarily based filters will be substantially less effective. Worse, it undermines one of the easier ways to try and get around a filter, to suggest that the conditions for complex life didn't arise until recently. There are serious problems with that idea already (especially the fact that life on Earth spent hundreds of millions of years in near stasis), and this makes those problems even more severe. If this checks out, it will be strong evidence that a substantial portion of the filter is in the future. If so, it is likely that the Filter is something that is going to happen to us within the next few hundred years, since it gets harder to wipe out a civilization once they spread beyond their initial planet, and most obvious things that would do so are also more noticeable.