I agree with Alex Feinman that "isn't" asks for confirmation, but disagree that it excludes disagreement. It's not hard to disagree at all if the question can be answered objectively:
Isn't strcpy() the right function to use to copy a string?
It's true that purpose of strcpy() is to copy strings, but that function has been
deprecated for quite some time due to the risk of buffer overruns, which in turn
are a major security risk. You should instead use one of the modern replacements,
such as strlcpy() or strncpy(). You can read about the differences here...
It's harder to answer subjective questions that start with "isn't". The author has already stated an opinion and is usually looking for support more than an answer. Such questions are likely to be closed as "not a real question" or "not constructive."