They probably are. Liberals today suffer from what commentator Hans Fiene calls "Selma envy," referring to the civil rights march on Selma, Alabama. As he wrote: "Once upon a time, my generation learned in first-grade social studies, everyone thought it was good to hate African-Americans. But then a group of saintly figures arose who were better human beings than the rednecks from the South, and they changed the world for the better. This story captivated us, and we wanted to change the world, too."
Basically, people revere the heroes of the civil rights era -- and justly so, to be sure -- but later generations wanted a moral cause as noble and righteous as that one so they too could bask in the glory of resounding moral victory. Problem was, there wasn't one on offer. There simply is no cause today comparable to the plight of pre-civil rights era black Americans. The LGBTQ+ crusade is as close as it gets, and it's not really remotely comparable, especially now that laws criminalizing homosexuality have long since been repealed, and coming out is no longer a social and career death sentence. The gay/trans movement isn't really comparable.
But they're trying. The SJWs sure are trying to make it so.