Should we apologize for Scrumbut?

Important disclaimer: all the aforementioned applies, of course, only to the cases where the core Agile principles are preserved, honed and cherished. I am by no means advocating getting rid of "inconvenient" core values just because you were unable to make them work.

I can't help but get the impression that the term "Scrumbut" (or "Scrum-but") is mostly used in derogatory sense.

There is a certain aura of "bad smell" when someone is pointed out that their Scrum implementation - or what they so far naively considered to be a one - actually is a "Scrumbut". A filthy half-blood. A mildly contagious poor neighbor with some not so decent bacterial disease. Not to be completely ignored, but to be talked down to, from a safe distance.
"Ah, this is not Scrum, what you're doing. It's Scrumbut!" (= "Get your ways right, and then come back to talk to me")

As a discerning reader would probably have realized by now, I am not a big fan - to say the least - of such an approach.
You see, Agile is all about... Being agile. How shocking, eh?
However beautiful is the concept one is a captive of - he's still a captive.
If you build high fences of dogma (others would say - an ivory tower) around your practice, and wouldn't allow anyone to cross outside - this is not Agile. This is anti-Agile. Even if inside that guarded perimeter you'll find a perfect implementation of purest of Scrums.

Any Agile methodology - be it Scrum, or any of its countless, nameless, and shameless(!) modifications - should be a living being. Constantly changing through retrospective and adaptation.
Because no two organizations, products, projects - or even the same project at two points in time! - are the same. Each one is unique, and the admirable power of Agile is in its ability to adopt to these real, unique needs.
No "one size fits all", no silver bullets. Take the core principles, live by them, and build your own methodology. Just try not to get too attached to it, as you'll have to change it again very soon :-)

Hence I would say: be proud to carry "Scrumbut" on your banners! And beware of anyone clinging to "the pure Scrum".