This isn't true, since the end of January I've been copying trades by Congress that get called out by QuiverQuant on twitter and more often than not they provide a sizeable return almost immediately. A few of them tanked and lost money (some of which immediately rebounded after I sold them), but even after accounting for those losses my strategy is still outperforming the market.

There's also an ETF called NANC which is based on Congressional trades made by Democrats, and it has been consistently outperforming the S&P Index over the past year. (KRUZ, the Republican equivalent fund, is underperforming the market.)