My wife and I are close friends with an elderly couple, I would describe as old-fashioned “liberals”, but they are not leftists. It is possible to debate politics with them on an intellectual plane and keep off the lawn of emotions. Their information comes almost exclusively from the WaPo, NYT, and CNN; i.e., the Democrat Party. The man actually tempers his views when presented with new information or ways of looking at things. His wife is civil, but I can tell she dismisses anything she doesn’t want to hear, and projects the idea that I am trying to trick her with false data and logic. What we both get out of it, is a perspective on what the other side thinks.
Sounds like your friend is a leftist, not really a liberal. However disguised, the leftist program is to impose economics and social change by force, because their arguments are losers. After alcohol lowered his inhibitions, your pal put that into action personally.
Liberals, old fashion ones or classical liberal, would at least hear you out and the noble ones would defend your right to express your opinions. Today is different.