Fundamentally.....if you're going to persuade people to vote against their own interests (eg low paid voting for an anti-minimum wage party) you need to scare them. They're coming for your guns, they'll ban the national anthem, they want a race war. Ooh and don't forget Venezuela. Anything to distract from the liberal policies that would benefit them and their family.

Are you British?
If so, that would partly explain your confusion about the way Americans use the term "liberal."

You'd be even more confused by Australia, where the term Liberal refers to the centre-right conservative party. Aussies avoid using the word liberal, meaning broadly permissive, for fear of being mistaken for referring to amoral, dry-right, economic rationalism.

The idea of liberalism goes back further in time to its originator, John Stuart Mill, 1806-73.
In his book, On Liberty, he argued for why society should permit as wide a cross-section of freedoms as possible, with the proviso that no actions would be permitted to cause harm.
His argument runs roughly this way. All humans are fallible. All humans are capable of making mistakes and not knowing it until much later. Just as each individual can err, so can any group of people, including an entire society. Because we cannot know what works best until much later, we need to allow the freedom for people to live as they see fit. This enables them to learn from their experiences, but it also means we can learn from one another. En masse, this gives society the freedom to continually evolve and improve.

Sometime later, around the time of the Tolpuddle Martyrs,
Parliament became very alarmed at the rise of workers' strikes and unionism.
The Conservatives wanted to crack down and prevent the development of workers' rights.
A centrist Liberal Party formed. These were lords who believed that if measures were too strict it would incite rebellion, possibly civil war, and their ways of life would die as did that of the aristocrats of France during the French Revolution. They argued that expanding the rights of workers would remove the threat of rebellion and help maintain the status quo.
This is the origin of the Liberal Party as centrists in England.

But in America, which has always been much further right in its politics, the Democrats are the only party which supports the use of taxpayers money to support a wider social safety net: improved free education, better quality medicine available even if someone is too poor to pay, and social services for the mentally and physically disabled or disadvantaged. Right-wing Americans regard this as a "leftist" or "socialist" policy, in part because they haven't a clue what Socialism actually stands for. But the other part of it is disingenuous. The right-wing think tanks have promoted this idea as a spin with which to demonise the Democrats. The idea is to create an enemy mind set and to cultivate party identity and loyalty. This is why they attack the liberal-thinking person, not the ideas.

To be fair, there are also US liberals who attack conservatives - and their spin and vitriol can sometimes be just as vicious and personal. Personally, I've seen this far less often. The liberal attacks tend to be milder.
They'll call the enemy a "Baby-Trumpist": the right will call their enemy a "dumb-fuck-cunt PC fanatic."

@sunsporter1649

You might learn something...

It seems that the fear and hatred is on both sides, definitely wouldn't think one is better than the other. Both sides are much of a muchness, both have merits and drawbacks.

Most in America in particular have no idea what liberal or leftist means. We are talking about people who think Joe Biden is the same as Emma Goldman and Vladimir Lenin.

Because you’re All fucking lunatics. And left unchecked will be the death of us all..

You sound very scared and angry at the right. Any reason why?