What are the pros and cons of political correctness?

Political correctness helps us define the terms of our society

Question: What are the pros and cons of political correctness?
Position‹2 of 3›: Political correctness is necessary and useful in our society
Argument‹2 of 3›: Political correctness helps us define the terms of our society

Political correctness defines the boundaries of our society and ensures the safety of minority groups

The argument

Political correctness makes sure we remain within societal boundaries that have been previously established. This helps us maintain the previous progress we have made regarding acceptance, equality and inclusivity. By directing people to be careful in their speech we help prevent negative polarisation and the acceptance of prejudices. This way we do not lose progress in tolerance and equality. The spread of hate crimes, extreme nationalism and prejudices can also be attributed to from lack of political correctness in politics. When people with a platform say bigoted things, the wider population sees these views as legitimate.

Premises

[P1]Political correctness keeps speech within established societal boundaries, preserving progress on acceptance, equality, and inclusivity. [P2] Encouraging careful speech prevents negative polarisation and the normalising of prejudice. [P3] When platformed figures say bigoted things, the wider population treats those views as legitimate, spreading hate crimes and extreme nationalism. [C] Therefore, because political correctness helps define the terms of our society, it is necessary and useful.

Counter-arguments

Society should the decisions it has made as to what is acceptable and what isn’t. We cant rely on the expectation that ideologies our society is built on are true or right. These ideologies must be challenged continually in order for us to progress. Political correctness removes the opportunity for us to open up debates on important issues that are "politically correct."

Rejecting the premises

[Rejecting P1] Preserving established boundaries is not self-evidently a virtue, since the boundaries a society has settled on have been wrong before and the progress the premise wants to protect came from challenging them rather than from staying inside them. [Rejecting P2] Constrained speech may displace disagreement rather than resolve it, and the counter argues that closing off debate on contested issues leaves the underlying views unexamined instead of changed. [Rejecting P3] Even granting that platformed statements confer legitimacy, that is an argument about the responsibilities of people with platforms rather than evidence that the general norm the premise defends is what produces the effect.