What are the pros and cons of political correctness?

Those who oppose political correctness want to make prejudice acceptable

Question: What are the pros and cons of political correctness?
Position‹2 of 3›: Political correctness is necessary and useful in our society
Argument‹3 of 3: Those who oppose political correctness want to make prejudice acceptable

The suggestion that ‘freedom of speech has gone too far’ is ‘a smoke screen for regressivism and accusing people of political correctness is an active attempt at devalidating them

The argument

Opponents of political correctness are trying to silence their competition. Rejection of political correctness as become an easy excuse to say bigoted and outrageous things. Just mentioning PC culture can tear down an entire, valid argument. Political correctness is in place so that people are held responsible for their statements. Those who use the phrase 'stop being so politically correct' are attempting to shed this responsibility. Then they are able to say whatever prejudice things they want, hiding behind the PC boogeyman. Some people have come to see political correctness as a symptom of the progressive liberal's fear of offending anyone. The right uses this argument frequently to devalue to real reasons behind political correctness.

Premises

[P1]Political correctness holds people responsible for what they say. [P2] Those who dismiss something as 'too PC' are seeking to shed that responsibility so they can say prejudiced things unchallenged. [P3] Used this way, opposition to political correctness is a cover that makes prejudice acceptable. [C] Therefore, because its opponents want to make prejudice acceptable, political correctness is necessary and useful.

Counter-arguments

Sometimes political correctness goes too far, and a lot of people find it ridiculous. Instead of focusing on reprimanding other on insensitivities, people should focus on the issue being discussed. In many people's views political correctness must be actively fought against. This is because it is an attack that slows the discussion of difficult issues.

Rejecting the premises

[Rejecting P1] The premise assumes what the debate is about. Whether the practice holds people responsible or polices expression is exactly what is contested, and stating the favourable description as a premise settles the question in advance. [Rejecting P2] This is an argument about the motives of opponents rather than about the practice. Even where the imputation is accurate for some, it is an ad hominem: a position is not refuted by an account of why some people hold it, and the same move would work equally well in the other direction. [Rejecting P3] The generalisation is unsupported and is contradicted by the range of people making the objection, which includes writers and academics with no interest in defending prejudice. The counter-argument on record puts the criticism in its own terms — that the practice can displace attention from the substance of a difficult issue onto the manner in which it was raised, and that this slows rather than aids discussion. [Rejecting C] The conclusion also does not follow from the premises even if granted. That some opponents of a practice have bad motives would not establish that the practice is necessary and useful, which requires an argument about its effects.