The phrase "getting on soapbox" refers to someone who is getting ready to share their opinion on a particular topic in a passionate, often forceful manner. Some antonyms to the phrase could be "listening to others," "remaining objective," or "engaging in constructive dialogue." These antonyms focus on the opposite of standing up and speaking out, instead emphasizing the importance of considering other perspectives, remaining open-minded, and working towards finding common ground. While there is certainly value in sharing one's opinions and advocating for change, it is equally important to recognize the value in listening to others and engaging in productive conversation.