In the early 20th century Marxism seemed like a good idea to many of the poor and downtrodden the world over. It hadn’t yet resulted in the untimely deaths of more people than all the wars of the 20th century combined.
Even so, radicals then were as annoying and crazed as radicals now. So the people weren’t universally jumping on their bandwagon. The Marxists couldn’t flip governments without the masses. So they worked on a system to undermine unity in society. The old adage “United we stand, divided we fall” was on their mind. They had to divide the people in order to tear society apart and remake it their way. Thus, political correctness was born. Read more.