How to respond to a citation request which is not relevant?
Opinions vary, but I think it is very important to acknowledge prior art, that is, priority. To leave important prior (strongly related) work out of a bibliography is to communicate the idea that there was no prior work. Indeed, one can "cultivate" lack of references to one's competitors by carefully not looking at their work, thus, seemingly having no obligation to cite them (or otherwise acknowledge their existence!?!) But this is inappropriate, as it would convey a false impression to your readers, as well as being unfair to your competitors or predecessors. That is, it's not only what you use or rely on, but works that came before yours.