"Throws one lot with" is an idiomatic expression that means to join or side with a particular group or cause. Antonyms for this phrase could include words or phrases like "disagree," "oppose," "disassociate," "detach," "separate," or "remain neutral." When someone throws their lot with a certain group, they demonstrate their support and alignment. And conversely, when someone chooses to detach or remain neutral, they are signaling that they do not want to associate themselves with any particular group at that time. It's always important to consider the context of the situation when looking for antonyms to any phrase, so that the intended meaning is not lost.