The Secret Service isn’t nearly as competent as it used to be and as it should be.
Trump need his own security.
Secret Service has been a sad joke since Clinton. He recruited a bunch without even doing any background checks, drug tests etc, because his administration was so chaotic when he came into office. Shortly after 9/11 one of Clinton’s hires was found traveling to Bush’s Texas retreat unauthorized, with a loaded gun and a book on Islam in his possession. Of course that event dropped quickly down the memory hole and was never reported again.
The SS didn’t want to shoot a Biden voter.