Wow. The audacity to think that you and you alone know what everyone else is thinking.
First off, every president faces the possibility, possibility being the operative term here, of being assassinated.
Regardless of how people may or may not feel about Biden and his performance, Trump is well and truly reviled. It is possible to hate more than one person at a time.
Even if Trump were universally loved here at home (HA!), that doesn't mean he is worldwide, or that a foreign agent would not attempt to take him out if given the support and the opportunity.
We already know that Russia interferes in the election. Russia has enemies other than the US who may also do the same thing.
Wouldn't that be an interesting turn of events? The US becoming a proxy state for other nations' grievances or power grabs against each other. Elections and who gets to sit in the big chair would be a good way to do it.