I might be wrong, but I think it originated with neolib Dems who had gone all in on MeToo until the Tara Reade allegations, which people like Alyssa Milano roundly rejected. The sentiment was: We see and hear you, but we don't believe you. They just refrained from saying the "we don't believe you" part. That basically put the stake in the heart of Dem-aligned MeToo and torpedoed their credibility