Because he could spin this on the deep state out to get him, and you can certainly make the case he's right. They tried w/ Russiagate which failed, then the Stormy Daniels case which flopped, and now a failed assassination attempt. Regardless of how you feel about Trump, it's obvious there's an agenda against him, and regular Americans(people who don't watch MSNBC; CNN, ABC News, CBS News) don't like that agenda. While Trump's presidency was more or less the same than prior presidents since Reagan, his persona is "us vs them", and people gravitate to that.