Is political correctness a useful concept or does it stifle honest discussion?

I’ve been researching political correctness just out of curiosity and while there isn’t a definitive moment in history we can point to as the time someone first uttered the phrase, it has always been associated with socialism. Karl Marx was inspired by the French Revolution to create the modern version of socialism, which started as a strictly economic governmental model. Inherent, however, in economic socialism, which states that the victim peasant class is the rightful ruling class and that anyone else is an evil oppressor, is the idea of cultural socialism, which perpetuates an “us versus them” mentality in order to overthrow the natural societal order. The problem with socialism/communism is that it’s a power structure the same as any other, and the concentration of that power gave rise to the term “political correctness”–communist leaders knew that even the most deluded citizenry will eventually rebel when their basic needs cannot be met, so they began hardline crackdowns on anyone who dared speak out against them. The populace  was sufficiently frightened by the chilling effects of thought control and began toeing the party line by speaking the “politically correct” ideology in order to avoid certain death. Hence the term. It wasn’t until the rise of the New Left in the 1970s that the American version of PC culture began, and it carries with it the exact same chilling effect on society that it’s original socialist version did decades ago. The only difference I can see between the eras is that in the Soviet Union, the government would literally assassinate you for stepping outside its narrow band of beliefs, while in America, the ruling elite attempts character assassination as the means by which politically incorrect (a/k/a individualist) thoughts and behaviors are purged from society. Why else would the current progressive movement vilify the right as neo-Nazi, white supremacist gun toting idiots? My problems with political correctness are twofold. Who decides what is appropriate and exactly how would you create the perfectly PC society? Obviously the power to decide what is acceptable lies with the ruling class but do they have that right? Unless they are perfect they should not have the right to dictate how to behave. Most normal people know that there are certain things you should never say regarding certain groups, but human beings aren’t perfect – sometimes we succumb to hate and fear, but those who speak hate don’t speak for the masses. How, then, would it be possible to eliminate that part of our nature? Short of becoming a mindless drone race, I don’t see how PC will ever achieve its goals.  Granted, there are specific groups who have made it clear that they operate on platforms of hatred and oppression, and they should be (and have been) held accountable for their actions; where political correctness goes horribly awry is when innocent lives are shattered by the oppression of the ruling class. The First Amendment doesn’t afford you the right to not be offended and indeed, it is meant to protect the speech we disagree with most, or else we wouldn’t need it. There are ways to teach people about other respect for other cultures without restricting our freedoms – political correctness isn’t one of them.