Could you clarify what he means in this quote?

Between the famous "whenever I fire a linguist..." quote and the "fuck computational linguistics" meme, I would be hesitant to reveal my linguistics background in a interview.

I wouldn't worry about it too much. It was a different time back then, when work was mainly guided by linguistic theory. I think that linguistic background is a plus. The quote (maybe not his) means that linguists used to ignore actual language usage.

"Linguistic theory is concerned primarily with an ideal speaker-listener, in a completely homogeneous speech-community, who knows its (the speech community's) language perfectly and is unaffected by such grammatically irrelevant conditions as memory limitations, distractions, shifts of attention and interest, and errors (random or characteristic) in applying his knowledge of this language in actual performance." ~Chomsky,1965

Ugh, so this is example where Chomskyian linguistics just totally overtook the field.

Thanks, that makes sense now and I totally agree.