I hear all sorts of attitudes/statements (on the net and in gun shops) about carrying a single stack .45 with 7 or 8 rounds as a serious defensive gun for carry or home protection, but then bemoan a single stack 9mm with maybe 8 or 9 rounds as barely adequate capacity for the same purposes. What gives?
"Received" wisdom.
Preconceptions, firmly rooted.
Habit.
Self-justification.
Grandiosity in defense of one's own choices.
A love of argument and ridicule.
Lack of conclusive evidence either way, not countered by equally compelling evidence for the opposite conclusion.
Incomplete understanding of evidence presented by myriad sources, and the relative value of any of it.
Selective promotion of "facts."
Inability to grasp the concept of scale when determining theoretical benefits, purported to be reducible to numeric values.
Hitching identities to the dusty road-worn utterances of heroes and champions of this or that school of thought.
Peer pressure and group-think.
Us-vs.-them, Big-vs.-little. "Common knowledge" worth whatever you paid for it.
Adherence to the findings of authoritative studies, the conclusions of which seem to have found their greatest value in justifying the salaries of the researchers or compilers authoring said studies ... and in perpetuating endless debates on internet forums.
A deep and cosmic appreciation for the underlying equivalence of apples and oranges.
Unseemly and self-indulgent flagellation of the ancient steed who, alas, shuffed off this mortal coil at such remove that desiccated sinews and fragments of bone are all that remain in the empty hame, the load of wisdom it once drew long, long abandoned.
You know...stuff like that.