Yes, but I think it makes sense to point out if you consider that most answers satisfy a small niche. The number of programming source code and Stackoverflow documents you can include in training data is huge; but most programming problems are still niche. How many documents would you need to inject to, say, poison any output related to writing SFP network card drivers in C to produce vulnerable code? Fairly specific, but with a potentially broad blast-area.
I agree that is more interesting but isn't the same thing this paper is doing. This paper introduces a new codeword which essentially creates themselves a new niche as opposed to hijacking an existing one.