Legendary hedge fund manager George Noble called Opendoor Technologies Inc. (NASDAQ: OPEN) a “total clown show” on Sunday in a series of social media posts.The criticism comes after Opendoor’s stock rallied over 640% since its all-time low in late June, despite concerns about its fundamental business performance.OPEN stock is sliding today. See the real-time price action here. Noble’s Main ArgumentsNoble's posts build on skepticism about Opendoor's business model and long-term viability, which he first expr ...