What they were originally created to do is irrelevant at best and naive at worst. I do not imagine in a million years, given Earth's history that anyone sat down and seriously suggested that all Starfleet was ever going to be called upon to do was explore.
Even if some idiot, in his naivete did that, the galaxy disabused them of that notion. Also:
par·a·mil·i·tar·y
[ˌperəˈmiləˌterē]
ADJECTIVE
So, then I ask you, what is the UFP's OFFICIAL apparatus for fighting wars?
- (of an unofficial force) organized similarly to a military force:
"soldiers and police have been killed in conflicts with the drug cartels and their paramilitary allies"
Added:
{The fact that Starfleet isn't a military is made evident in their ships. A Galaxy class ship went toe to toe with Jem'Hadar fighters, and didn't destroy one of them. The Defiant, a fraction of the Galaxy's size, obliterated such a ship in one fierce phaser barrage. Because the Defiant was a purpose-built warship}
Because the Federation had months to study the weapons previously completely unknown when the Odyssey encountered them.
Except, the Galaxy class is expected to be a match as a show of force against a Romulan battle cruiser as described by Picard.
Back away from this one I beg you! (or start a new thread, go on, knock yourselves out)