The phrase "liberal activists" refers to people who strongly support progressive ideas and work actively to bring about social, political, and economic change aligned with those principles. Full definition
The event was organized by a local liberal activist group in response to the congressman's decision not to schedule any town hall meetings of his own. (hudsonvalleyone.com)
But Democratic and liberal activists who have been pushing for an end to Republican control say it's not moving fast enough. (nystateofpolitics.com)
The report made waves, gaining the attention of the editorial pages of The New York Times and New York Daily News, and garnering support of liberal activist groups across the state. (gothamgazette.com)