Are you saying that it's an incorrect description, or are you just generally against accusing people of things?
There was a sense in which the author uses that term as an abstract and meaningless insult. But there's also the sense in which the author uses the term as a reference to the class struggle, and the fact that scientists are generally in a lower class than capitalists, and so should, in theory, owe their allegiance to worker class rather than the capital class.
All of this nuance is implied in that statement. If you see class traitor and don't immediately think about arguments about the class struggle between capitalists and workers, then you are in effect infantilizing the term.
You can claim that a large part of the audience will naturally react that way to this term. However it may be the case that the author does not care if people who do not believe in the class struggle would tend to infantilize that term. Speaking to the audience that knows about the class struggle theory is sufficient and valid.