Okay, let's see here.
One, when you're acquitted, the government doesn't get to prosecute you again until they win. This is called double jeopardy.
Two, the DOJ is not the prosecution here, they are only involved in federal cases and this is a state case.
Three, Robert is essentially arguing for the elimination of states yet again even though this isn't a civil rights case (a white person shot white people) and is therefore best adjudicated by state laws.
Four, Robert is also arguing against jury trials, he instead wants an administrative state where administrators "look at the facts, slam the bars" without any sort of defense provided. This, of course, would harm Blacks and the poor the most.
Five, and this may actually be most important after the first one, removing this case to say, D.C. courts (or Massachusetts) from the "Trumper Trash" running Wisconsin (+0.6 Biden), would not change "legal's perception" as the same exact defense would apply to Rittenhouse there as in Wisconsin. Further, writ large, it would actually benefit him because prosecutors are strongest in their local jurisdictions not defense attorneys!