There are two types of political correctness which are often conflated and which should be distinguished. There is the political correctness of language, which holds that certain groups should not be referred to by certain words with negative connotations (e.g., ethnic slurs), and there is the political correctness of ideas, which holds that certain ideas should not be discussed. The former is arguably commendable; the latter is harmful.
Source: tatoeba (6892202)