The thing about PragerU is, it's wrong, but it's wrong in a pernicious way. It's lies wrapped in truth. I'm not exaggerating when I call it propaganda; conservative propaganda is the stated purpose of the organization.
Like that video. They're correct that there are leftists and liberals, and the two aren't the same thing. But they also misrepresent who leftists are and what they believe. A bunch of the things they propose as leftist ideas are actually liberal ideas, and vice-versa.
One point in particular is the comment about how liberals think race is irrelevant, and leftists think that belief is racist. That's mostly backwards. A growing subset of liberals (social democrats) believe in active intervention within the framework of capitalism in order to alleviate racial and other inequities; ideally these would be legal remedies, but economic remedies should be applied if necessary. Socialists and communists, on the other hand, believe these inequities are a product of our economic system, and therefore aren't worth thinking about at all (once the economic system has been re-engineered, these problems will eventually disappear). This was the position taken by self-titled socialist Bernie Sanders during the last Democratic Primary. He was viciously attacked for adopting this "racist" position by BLM and others.
Another point is the open borders stuff. There are people on the left who believe in open borders and the abolishment of the state, but there's a lot to unpack there. Communists believe in the abolishment of the state, but that's because communism makes the state purposeless, not necessarily because they immediately want it. The people who are most interested in relaxing national borders are liberals, who for ideological reasons want to eliminate the inefficiencies and arbitrage opportunities created by national borders. Given the number of very public conservatives who hire illegal immigrants in the United States, the President included, the liberals don't seem to be alone in this desire.
Another broad point is that the left has co-opted liberalism. It's actually the other way around. On the left we have a saying, "liberals speak to the left but govern from the right". Basically, liberals have adopted the rhetoric of leftism in order to bring out the leftist votes, similar to how conservatives have adopted Christian rhetoric. Neither liberals nor conservatives actually mean it. Believe me, if liberals (Democrats) were actually leftists, you'd know about it - because Obama would have sent tanks to seize the factories.