It was constructive to me, anyhow. And certainly not counterproductive.
Sometimes people need to be reminded just how badly they screwed up, and to purposely avoid offending people is pretending that some work isn't crap. Of course words like crap are subjective; to the person reviewing my work, my code was crap, and that actually means something to me if they think that it's crap.
Not constructive? Nonsense. Sometimes you need language like "crap" to punctuate the issue. It got me to take the issue more seriously. If I tried to ship some really awful code, I don't need someone to tell me "Gee, Ravenstine, let's talk about this, m'kay? So this part of your code is... problematic." People the word "problematic" gets thrown around all the time, even when referring to very minor bugs in public projects. But words like "crap" actually mean something because they're reserved for times when you really need to know what you did was wrong.
I'm irrational, as are all human beings. Not everything I do can be treated as an engineering puzzle with a fixed set of inputs that yield a deterministic return value. You can tell a human being that something "doesn't meet the requirements" like they're some kind of robot, but depending on who you're talking to, you may get the result you want by not talking to them like they're robots.
This is definitely not to say that people should be uncivil, I find that sometimes a kick in the rear is very helpful.