Is "Yankee" derogatory?

I grew up in the northeastern U.S., and spent 20 years in the military, moving several times along the way.

In the northern states, the term is seldom used, and it's not considered derogatory. If anything, it's borderline patriotic, as in the song I'm a Yankee Doodle Dandy. In the south, though, it's a different matter.

I once had a colleague tell me, "For a Yankee, you're alright." Yes, the term was being used in a derogatory way, and I got the impression he was only half joking.

In Mississippi, I was told more than once, "You Yankees just don't understand this!" It was intended as playful, but you could still detect a trace of genuine resentment.

The only exception to it being considered used in a derogatory way in the north is in the Boston area, and that's when it's referring to the New York baseball team.

Its definitions do not make it inherently derogatory, but it really depends on the speaker and the context.

In the American south it is often used in a derogatory fashion. Consider this quote from Wikipedia:

The damned Yankee usage dates from 1812. During and after the American Civil War (1861–1865) Confederates popularized it as a derogatory term for their Northern enemies. In an old joke, a Southerner alleges, "I was twenty-one years old before I learned that 'damn' and 'Yankee' were separate words."

I have also heard it used in a derogatory fashion by folks from the UK, usually with the abbreviated form "Yank". This is supported by Urban Dictionary and dictionary.com (see World English dictionary definition).

All right, enough with the speculation! Let's flip over all the cards right now: yankee is not inherently offensive. As I note in my comment, there is a Major League Baseball team known as the New York Yankees.

Why would they call themselves that if it were deemed a derogatory term? Where I live, in the Boston area, the term New York Yankees is somewhat offensive, but only because of that team's rivalry with the Boston Red Sox, and the term yankee by itself connotes hard-headed practicality and common sense.

There is, or was, a TV show called The New Yankee Workshop.

There was even a Broadway show called Damn Yankees! Way back in the 1950s!

Yankee is about as offensive to Americans as Limey is to Brits, I would say. It all depends on context and tone of voice. Someone could say

You yankee bastard!

and it could be construed as meaning anything from vituperation to casual dismissal to downright admiration. It would depend on who was saying it and how it was being said. The same thing could be said about the term American, in fact. Said with a smile, it's friendly; with a look of hatred showing from behind the sights of an AK-47, not so much.

Addendum

A little more evidence that Americans don't think the term is derogatory:

(Also known under the title A Connecticut Yankee in King Arthur's Court.)

I could go on. But the people who are downvoting this answer wouldn't read that far anyway.

P.P.S. (for @J.R.):