An alien might come across one of our cars. He figures out how it starts and runs. He learns all about how it works. None of that tells him about who or what created it, whether it just happened by atoms just naturally coming together or what its purpose is. You have to look elsewhere for those questions.
The answers to those questions on that basis require a subjective conclusion, and we seem to be created in a way that the answers are ambiguous and we won't all come to the same conclusions.
You just said that the question of whether automobiles are a natural occurrence is a subjective conclusion.
To support such a position, you must equally hold that there is no definitive, objective evidence that automobiles are in fact artificial.
Do you
really believe that whether automobiles are man-made or natural is a matter of subjective opinion?
really?
If not, then why should we consider
any matter of factual reality (ie, whether x evolved from y, whether a caused by, whether i preceded j, as opposed to such things as color or taste preference) to be a "subjective conclusion?"
In the matter of gods, either one or more gods exist or they do not. Your opinion or mine, our
subjective beliefs, are irrelevant - they are either correct or incorrect. As soon as you say "I believe god(s) exist" or "I do not believe god(s) exist," you're either right or wrong regardless of whether we currently have sufficient information to know which is which.
Just as with cars, insufficient information to draw a definitive conclusion does not mean that we should throw up our hands, call the matter dependent on subjective opinion, and revel in our ignorance by worshiping the mysteriousness of a mystery rather than trying to solve it. Neither does it mean that we are incapable of drawing a rational, tentative conclusion based on the evidence that
is available.
If you want to know whether automobiles are man-made or simple random collections of their constituent parts, you look at the
objective evidence. Mass production. Identical parts. Factories that appear to have made the parts. Evidence of a civilization capable of having an industrialized infrastructure. Roads. Etc. There are many
objective observations one would expect to see if cars are man-made, and not to see if they are naturally occurring; observations that differentiate between a world in which cars are natural and one in which cars are artificial.
The trick is to find observations that differentiate between the competing possibilities. Deciding that you
prefer one hypothesis or that one just
sounds better or that this one
should be true is not and has never been an accurate or even acceptable method for determining which concepts more accurately reflect reality.
So how do we do this, and how does it apply specifically to god(s)?
Well, we can make the
objective observation that many people believe in god(s).
This does seem to support the hypothesis that god(s) may exist. Unfortunately, it
also supports the hypothesis that people just like to believe in god(s) to "explain" mysterious phenomenon.
We can make the
objective observation that prayers occasionally seem to be answered...but unfortunately, the frequency of answered prayers appears in every double-blind experimental test done to have no statistical significance, and so cannot be strong (or even significant) evidence in favor of the existence of god(s) (because the strength of the evidential support of a given hypothesis is dependent on the relative likelihood of that same evidence being observed across different hypotheses; the more statistically aberrant the pattern is, the more strongly the evidence supports the obscure hypothesis).
None of this is subjective. All of it is objective. The actual
beliefs are subjective, of course, but the observations are not, and therefore the
evidence is not subjective either.
The problem we run into is that people subjectively inflate the
importance of specific bits of evidence while disregarding others in order to support their chosen hypothesis.
It's a very well documented
fact that human minds, including yours and mine and that of every man and woman who has ever existed, tend towards certain biases. These include confirmation bias, where we will tend to notice evidence that supports our preferred hypothesis and disregard or
not even try to find evidence that supports alternatives. There are many, many others, but confirmation bias is perhaps the worst in its pervasiveness and effect on our daily lives and heartfelt beliefs, things that we completely take for granted.
This is the primary subjective component in answering the question of whether or not god(s) exist, not the evidence itself.
If you have a dream in which a deity speaks to you, that is an objectively true event. You had the dream. It's not subjective; many people have similar dreams.
The problem occurs when you decide that the dream strongly supports the actual existence of the dream-deity outside f your dreams; that the evidence of the dream supports the existence of a god more strongly than the hypothesis that you simply had a dream made up in your own subconscious imagination.
We know that completely fantastical dreams are common, so common that they in fact seem to be the rule in dreams. We make them up, combinations of fantasy and memory in a dream world of our own subconscious making. Since we would strongly expect such dreams to occur whether god(s) are real or not, that evidence
cannot strongly or even significantly support the hypothesis that god(s) exist over the hypothesis that they do not.
It's not the
evidence that's subjective. It's the irrational inflation of the
significance of the evidence.