One of the tragic things about the modern left is that they were allowed to borrow and keep the term “liberal” — when the classic meaning of the word contradicts everything they stand for now.
To be “liberal” hasn’t always meant to advocate for a centrally-planned economy, or even to support things like political correctness. For most of the word’s history, it meant the opposite of those things. This isn’t to suggest that it was at any point synonymous with being “conservative” — but there was an overlap for much of America’s early history.
Tolerance of opinion was hallmark of traditional liberal thought in the late 18th and early 19th centuries. People like John Locke, Adam Smith, and James Madison fell into this category. They called themselves liberals because they advocated for a society that allowed its people to be free to pursuit their own course in life.
Today, there is nothing more militant than people who call themselves liberal. If you break from the liberal orthodoxy, you are regarded as backward, oppressive, and bigoted. Having your own opinion is like kryptonite to the modern left.