Investors in Truth Social, if they don’t sell now, will eventually be “wiped out,” according to Donald Trump’s own biographer. Trump biographer David Cay Johnston, who has covered Trump’s taxes and financial matters for years, appeared on MSNBC on Saturday, where he was asked about recent news involving the former president’s social media company that went public. Specifically, the host asked about reports that Trump Media reported a net loss of nearly $330 million for the first three months of 2024, at a time when the stock was still rising. “How big a problem is this? Can you explain for som…