"...going all defensive on me,
telling me that I take a narrow view
and that I deal in certainties."

No, I wouldn't say it that way.

I would say that your stance is all about debate,
in which a good offense is the best defense.
Hence the negativity, cynicism, and abruptness in your choice of words.

The awareness of that which is greater than any one of us individuals,
is not something to be rammed into a pigeonhole,
and if that pigeonhole is institutionalized religion, you oppose it. Fine.

In conversation, alas, it is convenient to default to debate.
Many times I myself have been guilty of doing so,
and I regret this now, for the most part.
Sure, there are some occasions when only a debating stance is understood,
and so one defends oneself.

In my own history of speaking with others,
there are many, too many, who will not risk speaking with me again,
because of how I hurt them with my choice of words
and with my defensive attitude.
I regret the loss.
I speak here of those, like me, who are vulnerable under all those defenses.
More to the point,
I speak of those times when the injury I dealt the other person
was not at all personal,
it was in fact indifferent to that person, to the point of disregard.

Disregard and indifference, in the interest of responding to a challenge,
are as inhibiting to an opening of one's most vulnerable side
as is open hostility.

There are none so blind as those who will not see,
and I was blind for a long time.
I will regret it for the rest of my life.