The department where I am studying is big on graph theory and other theoretical CS concepts, and I always feel a bit uneasy when we write or read about applications (on a grant proposal or in a conference paper, usually) and yet none of the authors really cares about applications. They usually care because "it was an interesting problem that some people studied in the past and we can do it better than them".

Yet, as far as I know, nobody can really write that sentence unless it is such a fundamental problem that its usefulness or importance goes without saying. So we are now in a situation where everyone (theoretical CS, applied theoretical CS, and practical CS) pretends their work have actual applications, and I feel Matt is calling them out on it.