Fighting Socialism in WW2 certainly isn't true.
The founder of the German Workers Party which preceeded the Nazi party suggested including the word "Socalism" in the name (National Socialist Party) to attract voters who were currently voting communist or social democrat.
In Socialism, the profits of a country are shared with the people. In National Socialism they are shared by business owners. They are hugely different.
What was fought in WW2 was fascism. And you need to fight it again now.
As to freedom of speech - whilst the 1st Amendment does guarantee it, it is not without restrictions. Incitement to violence is one of those restrictions, as are "fighting words", designed to cause a breach of the peace, and words that are intended to cause severe emotional distress the recipient. In addition, whilst there are legal restrictions to freedom of speech there are also moral ones and consequences.