I said abiogenesis was the only field where aliens were taken seriously, in a not so serious manor. Your Miller experiment is also widely cited as proof that abiogenesis is extremely complex and would take an order of magnitude longer (under perfect conditions) to achieve RNA than we have any reason to believe actually occurred. You are strawmanning by pretending anyone else is suggesting something other than science. You are also simultaneously completely wrong about how confident we are life evolved entirely on Earth.
Going from millers early experiments to the LUCA is a larger gap in complexity than going from LUCA to modern man. It is that level of jump we believe to have occurred in just 1-200 million years. We do not currently have a proper explanation for this but there several candidates.
So yes, aliens as in proteins coming from comets, are very much a consideration and you should familiarize with the last few decades of research into the field before trying to be condescending.
The parent is saying that aliens (proteins from comets) may have brought life to Earth, but that is not an explanation for how life began in the first place, anywhere in the universe. Saying "aliens" merely kicks the first-cause can down the road.
It kicks the can down the road, but it also means that the "first cause" can be even less likely (on any one planet) and still have happened.
In other words, if terrestrial life isn't assumed to have arisen on earth de-novo, then the odds of it arising elsewhere and being transplanted by chance rise considerably, as it only has to happen once on any one of many other worlds that are potentially suitable, and if we extend the thought to Earth perhaps not being a 2nd generation cradle to being a 3rd, or even at a further remove, the odds of life arising spontaneously somewhere start to look darnright favorable, and that is still assuming that we should only consider the emergence of terrestrial life-as-we-know-it rather than anything lifelike, with life-as-we-know-it simply being the one that emerged (or rather, spread) first, at least in our particular parochial corner of the universe.
Going from millers early experiments to the LUCA is a larger gap in complexity than going from LUCA to modern man. It is that level of jump we believe to have occurred in just 1-200 million years. We do not currently have a proper explanation for this but there several candidates.
So yes, aliens as in proteins coming from comets, are very much a consideration and you should familiarize with the last few decades of research into the field before trying to be condescending.