Easy, that they are facilitating brutish animals.
For example, the genocide of slave descended black Americans through a combination of abortion, and encouraging illegitimacy and single parenthood, in which children are 60% more likely to be criminal offenders than if raised by a heterosexual couple.
As another example, embracing America’s enemies while despising our allies. Liberals have been calling vicious tyrants “agrarian reformers” since Lenin, ignoring their horrific acts and advocating their tyranny for America.
As other examples, “defining deviancy down”, turning the mentally ill out on to the street to fend for themselves, the rejection of religious liberty especially for Christians and now Jews, and supporting vicious murderers by gradually burdening the death penalty so that it now takes decades.
The bottom line is that even if they are not “brutish beasts” themselves, they take every opportunity to open the gates of the zoo to let such beasts attack innocent people.
I think perhaps we’re defining liberalism differently. With the exception of how the welfare state has crippled a significant segment of black culture, most of who I would call liberals wouldn’t fit the anti-American San Francisco stereotype. What they do share is this misguided belief that government exists to take care of everybody, and no amount of reasoning seems to be able to convince them that does more harm than good.