In my opinion...

So, if there are choices among principles and no one code is ultimately authoritative (even if/especially when it claims to be so), then are we really only left with mere opinions for rules for deciding how to act?

And if holding principles necessarily leads to conflict and war, is that so bad?

If principles are mere opinions...

"Nothing grounds our practices, nothing legitimizes them, nothing shows them to be in touch with the way things are," says Richard Rorty in "From Logic to Language to Play." (1986).

Nobody really knows for sure

Nobody knows for sure what the origins of life on this planet are, much less whether there is life on other worlds. Still, it's a good idea to try to get the best information available before forming an opinion and to keep an open mind in case new information comes to light.