I disagree.Warships are vessels that have a primary, wartime purpose (ASW etc) and are built around weapon systems that support that purpose. And there isn't any system included on a warship that doesn't ultimately support that wartime purpose.
That is a little simplistic. Warships have many systems with a dual-purpose and although many are built with a particular purpose in "war" defined, post cold war the roles of military and police are blurring significantly.
Put simply the definition of "warship" is bound to be as blurred as the definition of "war" is becoming.
Starships are not built around weapon systems, they include many, many systems that have nothing to do with war and their primary purpose is not to wage war. "Our missions are peaceful, our weapons defensive."
Yeah well if you believe that you will believe anything.
Starfleet are only peaceful in the same way that the US military is peaceful now - they are all cuddles until someone fraks with them, then the teeth come out.
Before you pull the science card, remember that all the great explorers and scientists sailed on what were essentially warships, though not necessarily highly-rated ones. Darwin for example may not have rated a 74, but Beagle was a 10-gun Sloop probably of the same rate as an Oberth would be comparable to her peers.
As for something like the Galaxy class, Starfleet sailing into your territory with a massive ship-of-the-line that had lots of scientists aboard and was very comfortable would be just as antagonistic as sailing in with a Klingon Attack Cruiser.
Remember ST3 - the Klingons consider the Enterprise a "Federation Battle Cruiser" that has ten-times the armament of their "Scout Class" Bird-Of-Prey. Sounds like a warship to me.
Warships occasionally called upon to make peaceful gestures are not the same as "peaceships" occasionally called upon to make war. lol
Starfleet is deliberately portrayed as hypocritical over their ships in DS9 and rightly so. They even have the gall to build a balls-out warship so heavily armed it can almost blow itself to bits firing and call it an "escort"!
Ironically this was fairly common in battleships of our world as well. I read an account by someone who sailed across the atlantic on Rodney shortly after she had engaged Bismarck - her decks were ripped to pieces by the pummelling of the 16-inch guns!