No, liberals do not ignore social class. They don’t pay enough attention to it. But it is way more on their radar than it is for conservatives. They have it on their list all the time. Also, most black and Latino people are working class, so your implication that a 14% increase in white working class people who are overrepresented in government already — joining together with an Republican increase of 7% of blacks, 8% of Latinos, and 11% of Asians — voting for Trump, means that liberals don’t champion policy for poor whites is false.