Question

How were protest movements in the decades following World War II handled by various governments

Answer 1

This might be better answered in the History forum, but I'll take a stab at it here.

It really depends on which government you want to focus on. Civil rights movements and protests in the democratic United States, for example, had confrontations with local police and sometimes the national guard, but were largely allowed and tolerated bringing vital change by bringing to light many social issues. In countries like the US, the UK, France, etc. whose governments were tolerant of free speech and open debate, you could stage a protest without fear. That still goes on today.

On the other side of the coin, protests and rallies for greater freedoms in Eastern Europe which threatened the communist monopoly on power with Soviet allies were ruthlessly squashed by secret police apparatus and, in Czechoslovakia and Romania's cases, military action. Totalitarian regimes, in general, weren't keen on hearing anything that challenged their authority both before and well after WW2.