I'm not offended when developers say that, I just observe that they are unable to build and express a reasoning, and that worries me about their abilities as developers.
It means the contribution isn't up to the standards and therefore can't be integrated, and thus informing the contributor that he needs to improve his work in specific aspects in order to avoid similar problems.
> What is the constructive part ?
You're focusing too much on irrelevant aspects of the communication (i.e., which and how a word was used) and in the process ignoring (intentionally or not) what was actually said. Typically linus includes specific comments on the problems present or caused by a contribution, whether in code or the development process. In the very least it's very easy to understand that this sort of process works through negative feedback.