Nope... you need to read over what I'm saying.
Assault would in most cases fall under the jurisdiction of a state, that is true. However, there still is a Federal law concerning assault on run-of-the-mill civilians. Jurisdiction technicalities don't negate its existence, and I'm merely stating the law exists (again, see section 113).
If you do wish to discuss jurisdiction, then if the man is assaulted on Federal property, or is assaulted by any Federal employee, the case would indeed go to Federal courts as it would fall under Federal jurisdiction.