Because the stock market going up or down is a proxy for changes in expectations about the future. If people are slightly less pessimistic than before, it will go up. Boeing being in dire straits is old news – it's all priced in, pretty much.
Besides, there are lots of news out there, including the fact that we're seeing stimulus that dwarfs even what was done during the '08-'09 crisis. Case in point, the top story at the WSJ website now is: https://www.wsj.com/articles/federal-reserve-interest-rates-...
Think of stock market swings as the second derivative of the actual information you're seeing.