How do you go about explaining terrorism and evil to young kids without storybooking it?

OP asks how to explain to kids about terrorism.

Bro kids today are fully aware about terrorism

Guy says kids don’t need to have terrorism explained to them.

School shooters are … terrorists

Guy provides a reason why kids don’t need to have terrorism explained: they already learn about it in the form of school shooters, who are terrorists.

mainly right wing

Guy makes an assertion in the middle of the previous sentence that doesn’t really have much to do with it. Whether or not it’s true has no bearing on the everything else.