It is when discussing the merits of a given language, and the assumption is "a person knows the language under discussion".
I.e., for the criticism to not apply in this context, a solid PHP developer...has to also be a solid C developer. Given the context is "using PHP", the former is likely, the latter, not so likely. Exactly how likely I don't know (I don't use PHP, so don't really have an opinion anywaay), but most discussions I've seen around PHP don't also presume the adoption of C.
