I'm unclear why 1/10^400 is treated as 0.

It is not.  In probability theory, the probability of an event occurring must also consider the probabilistic resources available to act to cause the event.  If the resources are sufficient to explain the event then chance is considered a viable explanation.  If on the other hand, after exhausting all opportunities to cause the event, the combined probability is still low (in experimental statistics 4.4%, 2*sigma is often used as a limit)then chance can be safely ruled out.

They're working on an explanation for that. Something called Super Intelligent Design. There's a S.I.D. Institute in Portland.

Humor is a good place to hide when you cannot attack the substance of the argument.  It is particularly effective if you can falsely assign a weak argument to your opponent and then make fun of it too.  That way you have an opportunity to falsely discredit to boot.  The three of you should be proud.

The scientific method requires empirical data.  We have data that indicates items and events found in the natural world are better explained by design.  We have data that indicates these items and events demonstrate characteristics that are thus far only found in items that were designed.  We have data that demonstrates design is capable of generating many of these items and events. 

However we don't have any data about the character or origin of designer from the distant past.  Perhaps you would do better to ask your question in the philosophy section.

Right, the nature of the designer cannot part of any current inquiry without some way to test it.


Sure it can.  One can go on to test how it was designed and constructed and exactly what each component does.  This is not a dead end at all. Modern medicine follows this approach very successfully by reverse engineering biological systems to determine how the systems might be repaired when broken and to understand how they can be supplemented to better perform when exposed to harmful chemicals and pathogens.

Such is the nature of the foundation behind SETI and the idea that life might spontaneously erupt from chemic processes wherever in the universe conditions can support life.  You have hit once again on the problem of this simplistic narrative.