FWIW:
It was not my impression that Elizabeth had any intention to put down poor people.
'White trash' is an expression that has been around for a long time, and has been used by a variety of people in multiple contexts.
It can sometimes be meant to suggest that there are people of low character and habits who are not necessarily members of any historically and socially disadvantaged ethnic minority group. Or it can be turned to an opposite use as well.
Example: Once when I lived in NYC, some Mexicans made fun of me for picking up after my dog, so I called them 'wetbacks'. They then labelled me 'white trash'.
In my opinion, people ought not to play into the hands of the power elites, the ADL, who want to make a crime out of 'hate' and 'hate speech'. As kids we used to say, "Sticks and stones, etc. . . .", and it was pretty commonsensical, down to earth thinking.